# 1969 RAM AIR III heads



## mrvandermey (Jun 15, 2011)

Hey guys, I have a question about heads...specifically '69 RAM AIR III heads. First, are '69 RAM AIR III heads good heads to use? I understand aluminum heads are better, but there is a local guy selling a set for $450. Second, do I necessarily need the full RAM AIR set up in order to benefit from using RAM AIR III heads? Lastly, will after market headers work well with RAM AIR III heads or should I use stock RAM AIR exhaust manifolds?

Any advice would be appreciated. Thanks.


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## Icefan71 (Apr 7, 2011)

Not an expert. I just like to read a lot. I'm pretty sure the RAIII heads were no different than any of the other D-port, small chambered (72cc), big valve (2.11/1.77) heads from 68-70. They are all desireable, but have the same specs. Maybe there is a difference in flow, but someone with hands on experience could answer that better than me. 

I've also read a lot that the RA exhaust manifolds fit and seal better with only a slight loss of power compared to headers.


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## geeteeohguy (Feb 2, 2008)

^^^^^this. Good heads, but you must use dished pistons to use them with today's poor fuel. If you just bolt them on, you will be stuck using race fuel. Too much compression. The RA manifolds are superior to tubing headers for a street/strip car in every way.


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## rvp986 (Sep 19, 2012)

OK. Now, I'm more than curious. Would someone please explain the difference between Ram Air III heads and.. say the standard heads you take out of a 400 GTO or Lemans, without Ram Air. I was interested in Ram Air heads when I rebuilt my GTO 400 and a buddy of mine... very knowledgeable about Pontiac engines, I might add sold me a set of nice clean heads for $350, that I rebuilt and used for my project. He said the Ram Air heads weren't worth wasting my time looking for. Besides, he said I'd pay an arm and a leg just to get them and they would not add 13 HP like I had been told in performance when engaging a Ram Air system. He did say something about the fuel of today, vs the fuel of yesterday. Sure it was all about the lead content... back then compared to the crap we're burning now.

So. With that been said should we all be burning Premium (91 or better octane) be a better choice? It would be nice if someone would give us a quick or somewhat detailed education here. My engines not running yet, but soon will.


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## mrvandermey (Jun 15, 2011)

Well I was able to pick up the RAM AIR III heads for the low price of $400. They are complete, but could use cleaning and likely a good rebuild (or at least a valve job and new valve guides). 

Geeteeohguy, thanks for the heads up on use on the heads. Before I use them, I likely to need to rebuild engine and heads. The heads are #48 heads, whereas my current heads are 7K3 heads. 

Besides the pistons and RA manifolds, what else do I need to get the benefit of these heads?


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## Icefan71 (Apr 7, 2011)

Rvp986, RAIII engines used the same D-port heads as on other engines. The difference was the cam and fresh air intakes. The RAIV, 455HO, 455SD had round port heads which flowed much better and are very rare.


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## mrvandermey (Jun 15, 2011)

So in short, if I do not have a Ram Air engine block (meaning the cam and/or pistons), is there any advantage to using RAIII heads (72 cc chambers) over the 7K3 heads (96 cc chambers)? With 91 Octane fuel as being the best here in California, will RAIII heads (with RA exhaust manifolds) perform any better than the 7K3 heads I currently have?

I have also noticed that the casting number "48" is used on both 1969 RAIII heads for the 400 as well as non-RA heads for the 350. How do I verify that these heads are RAIII heads? Also, looking up on a chart of Pontiac heads, I see that the #48 RAIII heads are for a Manual transmission. I am running a TH400 automatic tranny, is this going to be a problem?


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## BearGFR (Aug 25, 2008)

Having or not having a Ram Air block has nothing to do with how well the heads work to make power. The crank/pistons/rods make up what is called the "rotating assembly" and are not considered part of the block. The rotating assembly contributes to power output because the combination of bore/stroke defines the swept air volume - cubic inch displacement. The parts are installed _into_ the block. It can be a little confusing because the combination of engine block and rotating assembly is what is referred to as a "short block".

Likewise the cam shaft - not part of the block. The cam, lifters, pushrods, rockers, and valves collectively make up the "valve train". The heads plus valve train make up what is called the "top end" of the engine and is also the second primary determinant of power output because these parts determine peak volumetric efficiency (how much of the swept volume the engine can actually use) and also the rpm where peak VE occurs.


As already noted, RA III's are pretty much the same as any other D-port, large valve head. Do NOT try to run these with flat-top pistons on a factory spec engine even with 93 octane, let alone 91. You might as well take a hammer and knock holes in the tops of all your pistons before you even assemble the engine and save it the trouble of doing it for you. 

To use them with 91 octane, you'll need pistons with _at least_ 15 cc's of dish volume in the tops, assuming everything else is nominal.

With the 7K3's, you have the opposite problem. _ASSUMING_ that they are actually 96 cc's (they may have been milled, and also untouched heads can vary quite a bit from the published specs), you'll be at 8.144:1 on a factory nominal 400 bored +0.030, lower if it hasn't been bored. _IF_ the heads are 96 cc's and _IF_ they've never been milled, you could mill about .045 off them and get close to 86 cc's, which - along with zero-decking the block - would put you at 9.150:1. But before you start cutting on anything, make sure you measure everything, all the chamber volumes, piston deck clearance, head gasket compressed thickness and gasket bore size - first. Also, milling the heads that much is a one-way street. If you ever need to rebuild the engine in the future and have the heads "decked" to make sure they're flat, there won't be able to without leaving that surface too thin to use.

As far as ID'ing the heads. On any piece of Pontiac cast iron, always start with the 4 character date code FIRST - to determine the model year of the part. Then you can use the casting code to ID it correctly. (If they're model year 1969 with casting code 48, then they're both 350 heads AND RA III heads - it was the same head.)

Bear


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## geeteeohguy (Feb 2, 2008)

What Bear said, in spades. Me, I'd be measuring those 96cc heads and plan on milling them (and possibly the intake) to work on your block for about a 9-ish CR. I have a nice set of Ram Air heads, #12, sitting on the shelf because they are ping monsters on my '67, and that was with 94 octane fuel at the time. Running 87cc #15 heads now, and it's still marginal on a 100 degree day with 91 octane. Rule of thumb, to figure out what octane is needed with compression ratio: 8.7:1 needs 87 octane, 9.0:1 needs 90-91 octane, 10:1 needs 100 octane, etc. With today's pump gas , you are limited to a bit over 9:1 CR with iron heads.


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## mrvandermey (Jun 15, 2011)

I am so glad I am not deep into these heads. I am about $400 into them (a trade for a endura bumper). Well, I may just flip them to some one else. I truly wish I could afford a proper engine build and just go out and buy a set of new aluminum heads. But that simply is not in my budget right now. 

Now I see why folks just opt to drop in a LS1/2/6.....seems like it might be easier. This is one of those times I am having information overload. All roads seem to be coming back to an expensive rebuild, or just buying a turn key car. The good news is I can easily sell these RAIII heads. From what I am understanding, RAIII heads are the worst of the RA heads, do not make much difference, and these particular ones, are the least desirable of them all. I guess it is time to dump them.


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## geeteeohguy (Feb 2, 2008)

Woah, there, cowboy. Please tell us what you have and what you want to do with it. If you have a stock GTO and want to drive it on pump gas, a cheap-ish set of 87-97cc heads will do the trick. Installing an LS motor is a monumental project, and will net you an engine that has about the same HP but LESS torque than a standard GTO engine. These are simple cars with simple drivetrains. What engine/car/trans/rear gear do you have, and what are your plans? Cruiser, drag racer, etc.


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## bondobill (Oct 24, 2011)

Not trying to hijack this thread but I have kinda the same question as Mr.V
Been trying to help Brent sell a bunch of parts off his 400. Been looking for the going price on a set of date code 69 casting code 62 heads.
Only set I can find anywhere is for sale on ebay.
Guy says they are ram air heads code 62 and is asking $1600 for them. 

If I am getting this right, if there is no code on the heads stating that they where actually off a ram air engine what makes them worth so much more than a set of regular 62 heads. :confused

Bill


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## BearGFR (Aug 25, 2008)

A 1969 #62 head is a 1969 #62 head is a 1969 #62 head regardless of whether it was installed on a RA III block or on a "garden variety" YS 400 (like mine were). They were about as good as it got, perofrmance-wise, for Pontiac D-port heads. There's no way to prove whether any given example might have been originally sitting on a RA III engine or not.

... and ... _asking_ $1600 is a good distance away from _getting_ $1600.

Bear


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## mrvandermey (Jun 15, 2011)

geeteeohguy said:


> Woah, there, cowboy. Please tell us what you have and what you want to do with it. If you have a stock GTO and want to drive it on pump gas, a cheap-ish set of 87-97cc heads will do the trick. Installing an LS motor is a monumental project, and will net you an engine that has about the same HP but LESS torque than a standard GTO engine. These are simple cars with simple drivetrains. What engine/car/trans/rear gear do you have, and what are your plans? Cruiser, drag racer, etc.


There is not a short answer to your question. Realistically, I do not want to go through the motions of putting a LS1/2/6/7 in my car. It kind of defeats the nostalgic feel of a classic muscle car. I am not a strip (or even street) racer, so me looking for over 500 HP is not for me. I am a boulevard cruiser that likes the feel of power and have friend bouts of competition with my fellow hot rodders (Mustangs, Camaros, etc). 

Currently my car has no engine in it. However, I do have a 1972 YS code 400 engine with a set of matching 7K3 heads sitting on the floor next to my car. Ideally, I want to have a date correct engine in my car that puts out 430-480 HP on pump gas, preferably a Stroker 461. I have a 12-bolt posi rear end with very low gears (not sure specifically but believed to be in low 3's). Again, ideally I will be running 3.31 or 3.55 gears somewhere down the road. 

I just contacted a rebuild shop (Precision Engine Rebuild, out of Texas) to price having a RAM AIR III motor built. In my request for a quote, I needed to give the guy details on my car, current motor and what I am looking for. His short response was: "I think we should reman your block and heads." I am not sure what this statement means, but I am guessing from context that I should not go for a RAM AIR III motor and just use the motor and heads I currently have. 

Therefore, this leaves me with either using my current engine ('72 YS 400) or continue my search for a '68 Block, and then having it rebuilt into a Stroker 461, utilizing aluminum heads. Which means it will likely be a few years before my car is cruising down the boulevard.

So I am going to flip my RAIII heads to someone that feels it is important to utilize RAIII heads.


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## BearGFR (Aug 25, 2008)

At some point, you've got to make some decisions and stick with them. I'll give you a very quick example:
96 cc 7k3 heads on a zero-decked 400 running flat-top pistions = 8.42:1 compression - too low

96 cc 7k3 heads on a zero-decked 461 stroker w/flat-tops = 9.43:1 - too high for 91 octane

96 cc 7k3 heads on a nominal (not zero-decked) 461 w/flat-tops = 9.11:1 - just about right for 91 octane.

So, your 7k3's are pretty good candidates to use on a stroker build.

Want to use your other heads on a 461? It's possible to do _with the right parts_. KB-Icon IC-981 pistons have a 30cc dish in them. Put those in the motor, don't zero deck it, run those heads with standard gaskets and you'll be at 9.11:1 compression.

I would recommend having the heads reworked to have hardened exhaust seats installed, though.

What you've got to remember is that everything is related to everything else. If you take a bunch of random parts and build a car, you're going to have a car that runs and drives like it was built from a bunch of random parts. Think about every component from the front pulley on the crank to the rear axle, how they all are going to work together and affect each other. Just knowing that your axle is "somewhere in the low 3's" isn't how you do that. There's a world of difference in how a car with 3.31's behaves vs. how a car with 3.55's behaves.

If you want someone to build your engine for you and do it right, as far as I'm concerned there's none better than Jim Lehart at Central Virginia Machine. 


Bear


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## mrvandermey (Jun 15, 2011)

BearGFR said:


> At some point, you've got to make some decisions and stick with them. I'll give you a very quick example:
> 96 cc 7k3 heads on a zero-decked 400 running flat-top pistions = 8.42:1 compression - too low
> 
> 96 cc 7k3 heads on a zero-decked 461 stroker w/flat-tops = 9.43:1 - too high for 91 octane
> ...


I am so confused on this build. It really sucks not being mechanically inclined. It also sucks that I can not justify just spending the money to buy a turn-key motor or car for that matter. 

It appears from the wealth of information here, that buying a turn key motor and a turn key rear end is likely the best way for me to go. However, I do not see that happening anytime soon. For I simply can not justify spending $5,000-$10,000 for a motor and then another $2,500 for a rear end. The whole reason I have a project car is that I can not go out and buy a turn key car. 

I guess, this GTO project is going to get shelved for the time being, or at least the motor. I will sell off the parts I know I am not using and shelve the rest. If anything, I will focus on getting the chassis, body and interior right, then worry about the engine, tranny, and rear end some time down the road, assuming I do not loose interest first and sell off the whole project.


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## BearGFR (Aug 25, 2008)

Well, you can always GET mechanically inclined.  
It's like anything else. Acquiring the knowledge and understanding is possible with some effort. I knew ZERO about body and paint work until the sheer shock of being quoted 18-grand for a paint job forced me to learn. 

Bear


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## geeteeohguy (Feb 2, 2008)

You might be better off buying a complete, ready to go rebuilt engine for your car. Forget numbers matching.....There's a guy on ebay, I forget his handle but can try to find it (he's in the other forums) who has an excellent rep for selling rebuilt 455 engines, ready to go, for about 4k. His engines are mild, durable 400 HP builds that run great and last forever. Simply bolt in and go. 400 HP on pump gas will wake your GTO right up, and your worries will be over. With a mild gear like a 2.93 or a 3.08 and a TH400, the car will do everything well. If you decide to build your '72 YS 400, be advised that it is an excellent, high-nickel block, and is a perfect base for a nice build. Like Bear said, GET educated. It's fun, very gratifying, and it will save you a ton of money. If I still lived in Oakland, I'd be over at your place helping you out.


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## geeteeohguy (Feb 2, 2008)

Ok...did some digging and located the guy. His name is Bob Bohn, and he runs a shop out of Grand Rapids, Mich. called autobahn engines. He has short blocks on ebay ready to go $3600 and up (400cid) and has correct numbers for GTO's, so you could get a 'correct' block for your car. He has an excellent rep on the Performance Years board, and ships these engines crated. If you feel overwhelmed with assembly, combinations of parts, etc, this would be an easy and proven solution to your problem. Just bolt on your choice of heads and sheet metal, and install and drive.


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## mrvandermey (Jun 15, 2011)

Hey guys, I am back again with questions on heads. I know one thing, maybe I should go into business locating parts.....call me crazy, but I think it is a bit addictive locating parts.

Anyways, I now have 2 engine blocks and 3 sets of heads. I have had a '72 400 non-Ram Air block with '72 "7K3" heads on it siting in my garage. I now have a '67 400 Block (last 4 of casting is 6133 with a date code F057) with a set of '67 "670" heads on it (which may be RA heads). Plus I still currently have the '69 "48" heads (Ram Air III). Now here is where I need it explained to me in simple terms. I am not a racer, nor do I wish to be one. I like cruising and want to eventually have a 400-450 HP street cruiser. But right now, I just want a nice running car.

Can some one help me understand what I have and which combination will work best on pump gas (even if I have to change pistons, which is expected, right?).

I have heard that everyone wants RA III heads, but I discovered in this thread that that may not be the best choice. I have also heard many people say ignore the RA and just go for "16" or "670" heads, although, "16" heads could also be RA (confusing). It has been mentioned here that the "7K3" heads would work well for a 455, but I do not have that nor do I want that, so I am thinking the "7K3" heads need to go. 

I am liking the '67 block and I am leaning towards the "670" heads, but I obviously do not fully understand the mechanics involved. Oh by the way, there is a set of stripped down "16" heads that may be available to me (as if I really need to throw this in).


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## BearGFR (Aug 25, 2008)

Well, you've got to consider your constraints first. The big one is pump gas, which I understand in CA is going to be 91 octane. That means regardless of which parts you use, which engine you use, if you want it to be reliable and trouble free your target compression ratio should be no more than 9.1:1 - 9.2:1. Calculating compression ratio is simple. It's the ratio of maximum cylinder volume to minimum cylinder volume. Maximum cylinder volume is the sum of:
* "swept" volume (how much volume the piston "covers" between the top of its stroke and the bottom of its stroke)
* combustion chamber volume in the cylinder heads
* deck clearance volume (volume "left" over at the top of the cylinder if the piston doesn't come all the way to the top of the cylinder at the top of its stroke. Pontiacs "frequently" have their piston tops .020" down from the top of the cylinder at the top of the stroke)
* Head gasket volume (gasket compressed thickness and gasket bore size)
* Valve releif and/or dish volume in the tops of the pistons.

Minimum cylinder volume is all of the above measurements, MINUS piston swept volume.

Keeping all that in mind, using those 670 heads would be the worst decision you could make. 
Here's why:
* They have the smallest chambers, meaning you'll have to go to some extreme measures to "get back" enough volume elsewhere to get the compression down.
* They're closed chamber heads (has to do with the shape of the combustion chamber) and that causes them to have relatively poor combustion efficiency (takes longer for the fire to burn) which means they need MORE ignition advance (more time for the fire to burn) - which is exactly what you DON'T want in an engine that is already prone to detonation.

Now let's rub some math on the situation and see what it would take for you to run those 670's (which probably have "about" a 69-70 cc chamber).

Pontiac 400 bored +0.030: 4.150 bore X 3.750 stroke = 50.724 ci = 831.55 cc's
Deck clearance: 4.150 X .020 = .267 ci = 4.37 cc's
Head gasket: 4.160 X .045 = .612 ci = 10.03 cc's
Chamber: 4.270 ci = 70 cc's

Add all that up: Max volume = 915.55 cc's
Subtract swept volume = 915.55 - 831.55 = 84.4 cc's
Static compression ratio = 915.55/84.4 = 10.853:1 
Ain't no way that's going to fly on 91 octane

Notice we didn't include any piston dish volume yet though, so how much dishwould we need to bring that down to 9.1:1?
Turns out we need about 19 cc's
915.55 + 19 = 934.55
84.4 + 19 = 103.4
934.55 / 103.4 = 9.038:1

(Me, I'd probably go 20 cc's just because of the amount of ignition timing those 670's are going to need and I'd want some safety margin.)

If you go through the same exercise using those 48's (72 cc's), you'll find you need 17 cc's of dish to wind up in the same place.

If you use the 7k3's (96 cc's) then even if you zero-deck the block (which eliminates the deck clearance volume) and run the minimum dish volume (about 6 cc's for the valve pockets that have to be there, otherwise the valves will hit the pistons) you'll find that all calculates out to 8.423:1 --- which is too low.

"Bear" in mind this as well: Getting 450 hp out of a pump gas 400 ain't happening, not with any of those heads, and not with a cam that would be anywhere close to streetable. It's just not. If you want 450 hp out of any of those 400's you've got two choices: 1) build it into a 461 or 2) build it into a race only engine that requires racing fuel and would be miserable on the street (translation: you'd get your butt handed to you by anyone with a well set-up and torquey _street_ engine in any situation except for a race track.)

There's yet another problem with any cylinder head manufactured prior to 1975, the year unleaded fuel became mandatory. The exhaust valve seats weren't induction hardened - they didn't need to be. The lead in the fuel served as a cushion for the (extremely hot) exhaust valves slamming into the (extremely hot) exhaust valve seats. Without this cushioning effect of the lead, and without hardened seats, what can happen under load is that the exhaust valve seats can actually recede into the head from the constant pounding of the exhaust valves. Prevention means "babying" the engine all the time, or having the seats cut out and replaced by hardened seats (yet another machining operation that costs money AND can be risky if not done right - can you envision the damage that would happen if a ring of hardened steel were to fall out and start rattling around the valve head, chamber, piston, and cylinder at about 5000 rpm?)

To answer your question though, given the contraints you gave (pump gas and you want a 400), your best option is to run the 48's with 17 cc dished pistons (the 48's have better chambers than the 670's and don't need as much ignition timing).


Option 2: 72'cc Edelbrock aluminum heads, flat top (6 cc) pistons, .020 X 4.150 deck clearance = 10.02:1 -- which is ok _because these are aluminum heads._

Neither will get you to 450 hp though.

Option 3: 461 stroker 4.155 bore X 4.250 stroke (use the same 400 block), 7k3 heads,
.020 X 4.155 deck clearance = 9.11:1
450 hp is within reach without too much trouble.

All open chamber D-port, large valve Pontiac heads are essentially the same. 62's, 48's, etc are all 72 cc's and have 72 cc's in the chamber, pretty much the same port shape and flow potential. 16's are a step down because they have smaller valves. They can be upgraded to the larger valves, but this of course costs money.

(And in case you didn't notice back in the math part of this, just one lousy cc of volume can make a difference and that ain't much. That's why I always enourage people to MEASURE EVERYTHING(!). Although the nominal values I use for factory chamber volumes, usual deck clearance, etc. are usually pretty close any given specific engine can and will vary from these measurements by several cc's for one reason or another. Getting compression right is something you want to be positive about. If YOUR 48's for exmaple measure just one measly cc larger or smaller than 72, that will make a difference of 0.1 in compression ratio - higher or lower - and that's enough to push an already borderline engine over the edge into detonation territory)

Bear
*


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## mrvandermey (Jun 15, 2011)

Bear my friend, you might quite possibly be the closest thing to a "Genius" that I have ever met. You are simply amazing with the wealth of knowledge you have. 

That said, I find it interesting that so many engine shops (I have seen online and talked with a couple over phone) say they prefer the "670" heads and some say the "16" heads. Yet, as you have shown in the complicated math, the "670" heads appear to be the worst of the bunch. 

Okay, I think when I am ready for a 461 Stroker, I think the best bet would be to break down and buy a set of Edelbrock aluminum heads. However in the mean time (since I want to drive my car), if I want to make essentially a stock 350-360 HP engine, which of the heads (if rebuilt with hardened guides/seats) would provide the best results?

Reading up on the stock numbers (I accept the stock numbers may not be actual due to variances), I see that the "670" and "48" heads both have 2.11/1.77 valves and 72 cc; while the 7K3 have 2.11/1.77 valves and 96 cc. Does this mean the "670" and "48" heads are essentially the same heads? If not, what is the difference? 

Bear, you mentioned "milling down" the 7K3 heads to something like 84 or 86 cc.....that seems odd to me for 96 cc seems bigger than 86 cc.....so maybe I am not grasping what the cc encompasses. I was under the impression the cc is the size of the chamber where valves are at, and it seems to me if you "mill down" the chamber it would make the chamber bigger, hence a bigger number. Why am I off in visualizing the cc's in my mind?

Presumably, both engines I have ran before they were removed form their respective vehicles. Both engines I have include the heads that came with that engine (as well as the rest of the engine, including all bolt-ons), for the '72 block came with the "7K3" heads, while the '67 block came with the "670" heads. I have not heard or seen either engine run. Now the '67 engine, the previous owner appeared to know more about his engine and appeared to be more upfront about it. He had it in a '67 GTO, but said he got it from a guy with '68 GTO (the date code shows June 5, 1967). The seller mentioned he was driving down the road, heard a "knocking" sound and immediately shut down car, had car towed home and yanked engine out. Since he had always planned on putting a Chevy 454 in his car, he decided to part with engine. So I picked it up, a complete engine for the price of a bare block. He has mechanic skills and says he recognized the knocking to be from the bearings. He told me, at the minimum, I will need to either replace the crank or have the crank grounded down and then get matching bearings. Any opinions on the '67 engine?


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## geeteeohguy (Feb 2, 2008)

The '67 engine will be fine after teardown and inspect. Most likely will need just a crank grind, and new rods. No issue. To decrease the chamber size of the head, the SURFACE of the head (where it meets the block) is milled. The chamber is not milled/machined. Think of it as taking a half of a walnut shell and rubbing the open side across some sandpaper, many times. You will decrease the size of the 'cap' or 'dome' of the shell by filing the sides/face down. Same thing with heads.


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## mrvandermey (Jun 15, 2011)

geeteeohguy said:


> The '67 engine will be fine after teardown and inspect. Most likely will need just a crank grind, and new rods. No issue. To decrease the chamber size of the head, the SURFACE of the head (where it meets the block) is milled. The chamber is not milled/machined. Think of it as taking a half of a walnut shell and rubbing the open side across some sandpaper, many times. You will decrease the size of the 'cap' or 'dome' of the shell by filing the sides/face down. Same thing with heads.


I just want to make sure I understand this, for it is bad enough I am not knowledgeable on this matter, but when I go to a machine shop, I really do not want to sound like a walking moron or idiot. 

From what I am understanding, of the three sets of heads, the "48" heads (as long as I use dished pistons) and the "7K3" heads (with minimal decking and flat top pistons), will work well should I go for a 461 Stroker. While the "670" heads are just the worst choice.

Okay, now that I understand Stroker issue, let's set aside the Stroker idea for now (money and time being a factor) and focus on getting one of the two engines running, set to a factory setting of around 350-360 HP. 

Is there an advantage to using either the '67 or the '72 block over using the other? For a stock factory setup (again assuming the factory numbers of around 350 HP), which of the three sets of heads will provide these numbers? Is it likely that any of the three sets of heads will need hardened seats and a valve job? How will I know if I need to preplace springs as well? Should the heads also be machined or such?

Geeteeohguy, you mentioned two things of interest to me, you mentioned that the '72 block is a "high-nickel block", is that a good thing? What about the '67 block? You also mentioned that the '67 block may need a crank grind, how do I discover how much of a grind it will need? Then I buy new bearings to match, correct?


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## BearGFR (Aug 25, 2008)

Thanks for the kind words, I'll be sure that Mrs. Bear knows I'm a "genius" --- she'll get a kick out of that one.

Yes, both 670's and 48's are listed as having 72 cc chambers (although my good buddy GeeTee says 670's usually run small and I believe him.)

The main difference is in the shape of the chamber itself. Here's what 670's look like:
http://www.wallaceracing.com/closed.jpg

and here's what 48's look like:
http://i919.photobucket.com/albums/...es/Pontiac/PontiacD-PortHead-ValveUpgrade.jpg

See the difference in shape? The shape difference has a huge impact on the way the combustion flame travels through it after it gets lit. "Closed chamber" heads like the 670's are inherently less "efficient" than are open chamber heads, the fire propgates slower, so in order to build cylinder pressure you've got to light it earlier. There are two problems with that. One is the increased propensity towards detonation that we've already talked about, the other is less obvious. If you light the fire earlier, that means more time will go by before the piston reaches TDC and begins it's way down. You're beginning to build cylinder pressure while the piston is still on its way UP. The pressure is now working against you. Instead of helping to turn the crank and make torque, it's doing the exact opposite. Agreed, it's probably a very small amount - but it's there - and if you're trying to get all the torque you can out of an engine, it matters.

Bear


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## mrvandermey (Jun 15, 2011)

I see, I see said the blind man to his deaf friend.......

So, essentially, I can use either block, and of the sets of heads I have, the "48" and "7K3" would be best to use (accepting that modifications may need to be made to use either), but the "670" heads should be disposed of?


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## BearGFR (Aug 25, 2008)

That's up to you. Notice I didn't say those heads are "worthless". Quite the contrary. There are people (sounds like you've met some yourself) who are in love with those heads, and to someone who's trying to do an original restoration on a 67 GTO they'd be quite valuable. As I mentioned before, as long as the rest of the engine is built to set compression where it needs to be and the seat issue dealt with, they're even fine on a street engine. Personally, _at present_ I wouldn't have an interest in them (I like open chamber heads better and I don't have a 67 to restore.)

I try not to tell people what to do with their own cash and their own car, those decisions aren't mine to make, but I don't mind sharing my opinions and the reasoning I used to form them.

Bear


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## geeteeohguy (Feb 2, 2008)

What I would do: I would have both blocks checked and use the one that was in the best shape. A '67 block is also high nickel, and considered to be one of if not the strongest 400 block. The '72 crank will drop right in. The block with the smallest bore (not bored out a bunch of times or ever) wins. A stock stroke 400, with a nice set of dished pistons and any decent iron head, with the right cam, will rip your head off. The key is in the combination. An engine is just an air pump, and it needs to breathe. Pontiac figured this out pretty well. With a stock intake, carb, dished pistons, and a more modern cam designed for 9:1 CR, you will end up right at the same power level (350HP) as the original High Compression engine. As a side note, 670 heads are one of the best heads for making power the old school way. They work great at 11:1 CR. Good throttle response, excellent power, and use a lot of timing. They need 100 octane or better to work on a 400 with stock pistons. I know this from first hand experience. I had the same problem with 72cc Ram Air heads on the same engine. My #12 heads have open chambers, but yield way too much compression for a flat-top piston configured engine.


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## mrvandermey (Jun 15, 2011)

So Bear, based on your wisdom of shape of the chambers and out of pure curiosity (now that I see a difference in the shape of the chambers), what would happen if one were to mill off the little bumps in the 'open chamber" you showed me? Would there be any advantage to do so?


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## mrvandermey (Jun 15, 2011)

geeteeohguy said:


> What I would do: I would have both blocks checked and use the one that was in the best shape. A '67 block is also high nickel, and considered to be one of if not the strongest 400 block. The '72 crank will drop right in. The block with the smallest bore (not bored out a bunch of times or ever) wins. A stock stroke 400, with a nice set of dished pistons and any decent iron head, with the right cam, will rip your head off. The key is in the combination. An engine is just an air pump, and it needs to breathe. Pontiac figured this out pretty well. With a stock intake, carb, dished pistons, and a more modern cam designed for 9:1 CR, you will end up right at the same power level (350HP) as the original High Compression engine. As a side note, 670 heads are one of the best heads for making power the old school way. They work great at 11:1 CR. Good throttle response, excellent power, and use a lot of timing. They need 100 octane or better to work on a 400 with stock pistons. I know this from first hand experience. I had the same problem with 72cc Ram Air heads on the same engine. My #12 heads have open chambers, but yield way too much compression for a flat-top piston configured engine.



I like what I am hearing here on the blocks. On the '67, the seller was pretty sure it had never been rebuilt. On the '72, the seller had little information to give (he bought the car with it in, yanked it out to install a LS1). I am hoping at least one, if not both, are still original bore. The '67 was running on California pump gas, and is numbers matching for heads and block. So, it appears, I now have an engine I could use to drive my car at or near factory levels and another block that I could work on rebuilding into a Stroker 461. It also appears that the "670" heads will do just fine as a daily driver near factory specs and the "7K3" heads will work well with a Stroker 461 build. 

As for the "48" heads, they can be used, but are worth more to me as money for I am being offered twice what I am into them for, so the money will go much further for other projects.


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## geeteeohguy (Feb 2, 2008)

Again, 670's are far from optimum due to chamber shape. That said, I have first hand experience using closed chamber heads with dished pistons (on a 389) and the results were excellent. Went with dished ross pistons, stock 69cc 092 heads, and an XE268 camshaft. With a 3.36 gear and a 4 speed, that car will rip your head off, and runs on 89 octane without detonation. So, IF you use dished pistons, the 670's would work. Open chamber designed heads would, however, be the best choice.


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## BearGFR (Aug 25, 2008)

mrvandermey said:


> So Bear, based on your wisdom of shape of the chambers and out of pure curiosity (now that I see a difference in the shape of the chambers), what would happen if one were to mill off the little bumps in the 'open chamber" you showed me? Would there be any advantage to do so?


Some very MINOR smoothing of sharp edges is good, and I do mean MINOR as in just barely enough to take the 'point' off. Sharp edges tend to create hot spots which promote detonation. However, I wouldn't go beyond that. A lot of work went into those chamber designs and any major reshaping is not a trivial undertaking - best left to a professional head porter who KNOWS Pontiacs. (Translation: $$$$$)

Also, for the future when you do build the stroker - keep in mind that the additional swept volume (cubic inches) changes all the calculations for compression ratio. Take a 400 that's at 9.1:1 and stroke it to a 400, changing nothing else, and it'll be a lot higher than 9.1:1 afterwards. That's why those 7k3's at 96 cc's could be viable on a 461, but too big for a 400. Likewise running 72cc heads on a 461 is very tough to pull off (unless the heads are aluminum).

Bear


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## mrvandermey (Jun 15, 2011)

It seems that virtually none of the heads made by Pontiac work efficiently with Pontiac 400 motors for which they were originally designed for unless you modify the heads and/or block to compensate for unleaded fuel and California gas. That is something I am most certainly having trouble grasping. For example, 2 of the 3 sets of heads I have were originally mated to the engine that they are currently on and yet neither set of heads works efficiently with the motor associated with it unless modifications (i.e. dished pistons, milling of heads, zero decked blocks, and etc) are made. One would think I should be able to take stock parts, especially ones mated together from the factory, and make them work like they did from the factory. Mind boggling I tell you.


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## BearGFR (Aug 25, 2008)

Simple to understand. Back when these engines were new, 97, 98 octane (and higher) leaded fuel was readily available everywhere and was the norm. That all changed in 1975, the first year that unleaded fuel became "law".

Bear


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## mrvandermey (Jun 15, 2011)

So with all this said, if I just want to be practical and get either engine I have up and running (as close to factory specs as possible) with the heads that came with that respective engine, I will still need to modify the pistons, the valve seats and possibly do some milling as well, correct.


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## geeteeohguy (Feb 2, 2008)

I simply located and installed a set of 87cc Pontiac iron heads for my '67 GTO with its original 400. Runs well at about 9.3:1 CR except for pinging on the 105 degree days pulling long grades. The two heads I know of that have 87cc chambers are the 1970 GTO455 head, #64 ($$$$$) and the 1970 455 big car head, #15. 1968 #15's aren't 87cc. Have to be 1970 455. Drawbacks are smaller valves and press in studs. I had screw in studs installed in mine, but left the small valves. As I said, it runs well on pump gas. Straight bolt on deal, too. I didn't want to install dished pistons in an engine that was in perfect working order. Ran me about $1400 for the entire deal, because the heads I bought needed everything.


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## mrvandermey (Jun 15, 2011)

Well, I have done sold the '69 RAM AIR III heads, so maybe I should start a new thread, but I think I am carrying on with the preceding conversation.

I just talked to the seller of the '67 engine I have. He said he pulled it a couple months ago (it still has fresh oil and coolant in it). He said he drove it around for nearly a year using 92 Octane with lead additive. He does not believe the motor was ever rebuilt for it has stock factory bolts and the heads do not have hardened seats. 

Now, I am perplexed, first of all, where in California is someone getting 92 Octane? Next, is lead additive something I can pick up at the local car parts store? Here this guy was driving a '67 block with matching 670 heads in today's time just using 92 Octane fuel and lead additive. Is this what most folks are doing? I mean, there has got to be a lot of cars driving on the road that are either survivor cars, never been rebuilt cars or car rebuilt exactly to factory standards, how are they driving these cars when it has been determined in this thread that even though the old (pre-1975) blocks are mated with the very heads they originally came with, they do not perform as well and there are issues due to the unleaded fuel and lower octane levels.


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## geeteeohguy (Feb 2, 2008)

I don't understand what you are asking. We've posted what is. I can add this: I recently helped a friend complete the restoration of his '67 GTO here in central CA, and he is using the stock 670 heads. The engine is bone stock, with an 068 cam, standard bore. Original everything. He rarely drives it. When he does, he uses 110 octane aviation gas mixed with the 91 octane. I've been driving my stock '67 GTO since 1983. Even back then, it rattled like a can of marbles on 94 octane that was then available. So, if you want to build it stock, and run it, it will rattle on you. Have a co-worker who sold his stock '70 Bonneville with the 400 engine. It rattled too. He retarded the timing and it became a dog and it still rattled. So, do what feels right. Just telling you how these '60's high compression engines run on today's gas, using my 35+ years and 100's of thousands of miles driving them as a reference point. I gather it's basically what you don't want to hear, though. Take care.........


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## mrvandermey (Jun 15, 2011)

Geeteeohguy, you are right, not quite the answer I wanted to hear, but it now is all making sense to me. I am getting educated on it all. 

The stock engines and heads have trouble with today's low octane unleaded fuels, but I can rebuild the engine and heads (with modifications) to run and run well on today's fuels, correct?


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## ALKYGTO (Mar 29, 2010)

Stop, I'm biting my lip so hard it hurts.


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## BearGFR (Aug 25, 2008)

Well, several folks have put in a lot of time and effort to not only make recommendations and give you multiple options but also to explain the principles and logic that those ideas were based on. There's not much else anyone can add, if anything. It's up to you to choose a direction and live with the consequences. Your car, your cash 

Bear


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## mrvandermey (Jun 15, 2011)

BearGFR said:


> Well, several folks have put in a lot of time and effort to not only make recommendations and give you multiple options but also to explain the principles and logic that those ideas were based on.  There's not much else anyone can add, if anything. It's up to you to choose a direction and live with the consequences. Your car, your cash
> 
> Bear


Oh, I agree very much, that everyone here has been extremely helpful. As you mentioned, I need to get educated, and that is what I have been doing. I now know what direction I am going and have a good idea now of what is needed to get there. I now also have a much better understanding of how these old performance high compression engines did work then and does work now. 

As for the post regarding the 92 octane and lead additive, I was quoting what the seller of my engine did to make the engine run. I had never heard of this trick before and just wanted to know if this is a common practice. 

In fact, I have taken the knowledge you all gave me here and started to tear down the '72 engine. I am doing this to see how it is all together and why I am at it, see what condition it is in. As for my '67 engine, I know the direction I want to go, just not yet sure if my budget is in line with my plan. We shall see. 

By the way, what is a normal price range to have a set of heads rebuilt and have a engine block machined to be ready to be rebuilt? I have always pictured this cost to be $2K-$3K just for that, but honestly I have no idea whatsoever.


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## Taxangler (Sep 10, 2013)

I am just finishing a rebuild of my 1969 400 Ram Air III engine. I replaced the stock heads with Edelbrock aluminum heads. They run much cooler. Some of the particulars are as follows:	

Bore – 4.150; Stroke – 3.750; Compression – 9:5.1
	Edelbrock Performer RPM aluminum cylinder heads with matched
manifold ports; Intake runners 215 CC; Exhaust runners 175 CC; 
Combustion chamber 72 CC
	Valve diameter: Intake -2.110; Exhaust 1.660
	Spring pressure – 125lbs. @ 1.800
	Lunati Voodoo Camshaft; Lift @ valve intake - .504; Exhaust – 527; 
Duration @ .050 Intake - .233; Exhaust - .241
	Roller rocker arm ratio – 1.5
	Edelbrock Torker II single plane intake manifold: 3500 to 8000+ RPM
	Quick Fuel 750 CFM Super Street 4 barrel carburetor; Primary jet
size - .074; Secondary jet size - .080

The engine runs strong and sounds great on high octane pump gas.


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## rexs73gto (Nov 25, 2012)

I've read all of the posts here & am so surprised that no one has given you any idea of how much it's going to cost you to build your 461 stroker engine. I don't think you really have any idea of how much your going to wrap up in this engine before it's done. You kepp saying you want a stroker engine. You do know that you will be buying a stroker kit to do this , which will consist of a new crank & new rods & you wil also want to buy new pistons (forged) just to start. The crank & rods along with the bearings are going to run right around $ 2200.00 depending on where you get it. Pistons then again, are going to be around $ 500.00 for a set that will live in a new engine. Your machine work depending on your costs where your at for labor will be at least $ 3000.00 to do it correctly. Then you have your other parts , cam cam bearing. gaskets lifters, push rods rocker arms & all the mics. parts to put it together. Another $ 1800.00. Now for the part you've been talking about but not really understanding, the heads.The heads are not all the same weather they be Ram Air heads or std. heads. Ram Air heads are different as they do have a different port floor in them, thats what makes them better. Thats what makes them flow better, the non Ram Air heads are good heads, but you have to be aware that not all the heads have screw in studs, & if you go much over 300 HP, you will need the screw in studs because with the extra HP come the extra pressure. You will end up pulling out the push in studs right out of the heads , which will be no good at all. You can usually tell the better set of heads because they will have the screw in studs & those are the ones you will want. The 48's you had were very good heads & could have been used if you did go to a stroker 461 because the extra cubic inch helps in to dissipate the the extra pressure to keep the knock away better just because the extra size. Doing a proper rebuild yourself is always going to cost you a bit more then someone a pro. building you a create engine. Mainly because they are doing all the work in house so nothing is farmed out. But for someone like me who I always build my own engines so I can have complete control of it, I prefere it. You can buy a create engine from a pro like Jim Butler for about $ 6500.00 that will be 450-500 HP in a 461, or 462. Depending on weather you go for the 400 base or the 455 base & have a warr. No mater you are going to be into an engine (stroker ) for that much. Plus that will be an engine with alum. E-heads to. You can go to his web site to see what is offered. Just type in Jim Butler engines to see what is offered. He is a Pontiac guy only. You should know the name. Now just a short noter on your heads. The 670's are the 67 version of the Ram Air III heads, they were a similar design to the early 421 SD heads of 61-62, but as said they are closed chamber heads & require good gas which we don't have anymore. They were a good head then they were 360 HP heads in 67, but with the on coming emissions Pontiac along with everyone else went to an open chamber head. Remember that Pontiac take the compression out in the heads & not the pistons like a chevy so the difference in the CC's of the heads are where the compression comes out of. Most all the Pontiac heads need to be CC'ed to make sure you know what your working with, as most are not as advertised. That to will add to your labor price too. Also Pontiac pistons for all the 400's are the exact same piston they are all cast piston which for todays gas makes them junk. The ONLY engine that used a different piston for the 400's is the RA IV which used forged piston, in 69 & 70 only. The only 455 that used forged pistons were the 455 SD for 73 & 74. All the others used cast pistons to. Thats the same with all the engine lines ,,, again of course the 61-& 62 421 SD engines. Most all Pontiacs used a cast crane to, there were some armasteel cranks which are a little better & then the SD 421's used a forged crank. Personally I wouldn't use iron heads on any car unless it was a numbers matching rebuild, because by the time you do all that is needed to the heads to make them work with todays fuel you'll have as much in them as buying new Alum. heads, plus you'll have a better set of heads to work with if you ever want to go for more power. Enough for now , thanks for listening. Rex


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## ALKYGTO (Mar 29, 2010)

Good post but hard to read with no paragraphs. :crazy:


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## smcbride (23 d ago)

I bought a set of 62 heads to replace my 6x heads on a 455. The 62 head is a small chambered 78cc with good D port castings that clean up well. It is found on '69 428 blocks. It was sold to me back in the 80s as a RA III head. On my 455, I used HO Racing dished forged pistons, hooker headers, crane lifters, crane 1.6 rockers, special grind cam, edlebrock torq II mani, a rochester 780 carb, and the thing was a beast. It is supposed to be one of the best D port heads.


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## BearGFR (Aug 25, 2008)

My 69 came from the factory with #62 heads, and it was just a 'garden variety' YS coded 400. I think that RAIII heads carried different numbers, but honestly pretty much all the D-port, large valve, screw in stud heads all had the same ports and were essentially the same head. Differences, if there were any at all, between 62's and RAIII's would have been extremely small. 

Bear


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## ponchonlefty (8 mo ago)

mrvandermey said:


> So in short, if I do not have a Ram Air engine block (meaning the cam and/or pistons), is there any advantage to using RAIII heads (72 cc chambers) over the 7K3 heads (96 cc chambers)? With 91 Octane fuel as being the best here in California, will RAIII heads (with RA exhaust manifolds) perform any better than the 7K3 heads I currently have?
> 
> I have also noticed that the casting number "48" is used on both 1969 RAIII heads for the 400 as well as non-RA heads for the 350. How do I verify that these heads are RAIII heads? Also, looking up on a chart of Pontiac heads, I see that the #48 RAIII heads are for a Manual transmission. I am running a TH400 automatic tranny, is this going to be a problem?


the ram air 3 heads have 1.77 exhaust valves screw in rocker studs and 72-75 cc chambers if not surfaced. if you keep compression 9-9.5 the performance will be noticeable.if you have them ported the performance will be very good if racing. the automatic will take more power to turn but the heads will work fine.


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## BearGFR (Aug 25, 2008)

ponchonlefty said:


> the ram air 3 heads have 1.77 exhaust valves screw in rocker studs and 72-75 cc chambers if not surfaced. if you keep compression 9-9.5 the performance will be noticeable.if you have them ported the performance will be very good if racing. the automatic will take more power to turn but the heads will work fine.


Same as #62's


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## ponchonlefty (8 mo ago)

BearGFR said:


> Same as #62's


as far as i read, yes. the knowledge on here is awesome. i have 16s and they came on 68 gto with big valves and screw in studs from the factory. there are two different 16s apparently from what i've read.


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## O52 (Jan 27, 2019)

Yes there was. 1968 '16s' were big valve, 1970 16's were small valve. Which is why the dates are important when buying


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## PontiacJim (Dec 29, 2012)

ponchonlefty said:


> the ram air 3 heads have 1.77 exhaust valves screw in rocker studs and 72-75 cc chambers if not surfaced. if you keep compression 9-9.5 the performance will be noticeable.if you have them ported the performance will be very good if racing. the automatic will take more power to turn but the heads will work fine.


Aha, a 2014 forum post revived.

1968 Ram Air heads had 2 versions. Early 360 HP RA I with D-port exhaust (744 cam for manual & 068 cam for auto), 366 HP RA II with Round-port exhaust(June) and a different combustion chamber shape that was the same as the later RA IV heads (used the 041 cam 1.5 ratio rocker arms). Blocks on the RA II are said to be 4-bolt mains.

Using .406" lift number comparisons - The RA II heads flowed 194 CFM @ .400" lift in stock form Pete McCarthy book - (1970 RA IV - 225 CFM @ .400" - Wallace site). RA III - flowed 215 CFM @ .400". Most big valve D-port heads flow about 205 CFM's @ .406" lift.

The #48 heads were also used on the '69 350CI HO engine. Seems they were smaller chambers which would make sense as smaller chambers were needed for the smaller cylinder bores to keep compression up. However, in a long discussion over at the PY site, a couple original #48 heads on 400CI blocks also turned up with the smaller CC chamber heads on them. But in general, the 400 head would have been 72-74 CC's.

Early 1969 RA engines with manual trans used the "744" cam and this was soon changed to the "068" cam - said to be a little more streetable. Automatics got the 068.

The 366HP RAIII engine was a package. It was not solely about the heads. It was the RA exhaust manifolds, cam, matched/jetted carb, distributor with a timing curve specific to the engine. The RA hood set-up was standard, but you could also add this to any GTO as an option for more money. Standard ratio rear gears were 3.55, 3.23 w/AC. It was also about "image."


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## smcbride (23 d ago)

I like this youtube channel, and it just happens that they rebuild a set of 6X heads from a 400. The combustion chamber looks like it would create a lot of hot spots and really is a waste to try and use them for any kind of performance build as a start. I saw some RAM Air III heads online for under $800.

Take a look at this rebuild video and see if you like the head. They have a bunch of videos.


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## PontiacJim (Dec 29, 2012)

smcbride said:


> I like this youtube channel, and it just happens that they rebuild a set of 6X heads from a 400. The combustion chamber looks like it would create a lot of hot spots and really is a waste to try and use them for any kind of performance build as a start. I saw some RAM Air III heads online for under $800.
> 
> Take a look at this rebuild video and see if you like the head. They have a bunch of videos.


Typical Pontiac combustion chamber - some are deeper for more CC's. RA III will be the same as any 1968 - 1970 D-port head.

Here is my 1972 7K3 Heads cleaned up.


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## ponchonlefty (8 mo ago)

PontiacJim said:


> Typical Pontiac combustion chamber - some are deeper for more CC's. RA III will be the same as any 1968 - 1970 D-port head.
> 
> Here is my 1972 7K3 Heads cleaned up.
> 
> ...


it looks like you unshrouded the valve. did you go by the jim hand book?


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## PontiacJim (Dec 29, 2012)

ponchonlefty said:


> it looks like you unshrouded the valve. did you go by the jim hand book?


Yes, I did. Chambers came out to be 98 CC's and most numbers seem to reflect 96 CC's as stock. I opened up the throats per Jim Hands technique, opened up/equalized the pushrod bulge, gasket matched to RA IV size, boattail the valve guides, smoothed things out. Had one port flowed and I got 235 CFM @ .550" lift. Thought it might be more, but still good for my build.


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## ponchonlefty (8 mo ago)

PontiacJim said:


> Yes, I did. Chambers came out to be 98 CC's and most numbers seem to reflect 96 CC's as stock. I opened up the throats per Jim Hands technique, opened up/equalized the pushrod bulge, gasket matched to RA IV size, boattail the valve guides, smoothed things out. Had one port flowed and I got 235 CFM @ .550" lift. Thought it might be more, but still good for my build.
> 
> View attachment 160134
> 
> View attachment 160135


thank you,for the detailed pics.i have been studying up on porting but the pics. help me see what i need to do.


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## Baaad65 (Aug 29, 2019)

PontiacJim said:


> Typical Pontiac combustion chamber - some are deeper for more CC's. RA III will be the same as any 1968 - 1970 D-port head.
> 
> Here is my 1972 7K3 Heads cleaned up.
> 
> ...


Mine are 92cc..Viva la 7K3!


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## PontiacJim (Dec 29, 2012)

Baaad65 said:


> Mine are 92cc..Viva la 7K3!
> View attachment 160151


Yep, I could drop my chamber CC's by milling the heads, but did not do that as when I factored allmy dimensions I came up with 9.01 compression. However, when I actually assemble my short block, I want to measure how deep in the hole the piston is to verify what my machinist told me to be .020". I still may have them milled slightly to get my compression up just a little more - so the jury is still out on this one.


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## Baaad65 (Aug 29, 2019)

PontiacJim said:


> Yep, I could drop my chamber CC's by milling the heads, but did not do that as when I factored allmy dimensions I came up with 9.01 compression. However, when I actually assemble my short block, I want to measure how deep in the hole the piston is to verify what my machinist told me to be .020". I still may have them milled slightly to get my compression up just a little more - so the jury is still out on this one.


My build sheet shows they were shaved .060 and the intake side .050


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## PontiacJim (Dec 29, 2012)

ponchonlefty said:


> thank you,for the detailed pics.i have been studying up on porting but the pics. help me see what i need to do.


First thing, have your heads hot tanked and magnafluxed for cracks before doing any work. My description below is from what I did as an "amateur" as I do not port heads for a living. I have cleaned up several heads in the past to improve them, but not go for any kind of maximum flow and never had a set flowed on a machine until this set. I know enough to be dangerous and my goal was to simply clean up the heads and get a little more than stock flow - which I did. In theory, the extra flow should support the estimated 425-450HP I hope to have while keeping port velocity high for a nice responding engine.

Jim Hand's book was my guide in prepping the heads and enlarging the port throats. BUT, if you want a really good video showing all this, the tools, the templates, and testing. Purchase the *Performance Porting* video from Pete McCarthy. Well worth the price. 






Pete McCarthy Books


Purchase books and video by author Pete McCarthy on all things Pontiacs




www.petemccarthybooks.com





It was not too difficult to do. I use a high speed die grinder (an old Makita I have) and a carbide bit. Then sanding rolls. You can buy a kit that has all the sanding rolls and the rod needed that they will fit onto. I have had this kit for 30 years because I have not done many heads. I see even Harbor Freight has a small inexpensive set. Most seem to have only the shorter shaft for the sanding rolls. My kit has a short and long shaft so you can get down into the intake runners. You can do some clean-up on intakes and I used it on my brother's cast iron exhaust manifolds to clean them up.

Used a Sharpie to "color" the area around the ports and then lay the intake gasket on and use a scribe to follow the gasket port shape for grinding. The carbide cutter cuts fast and I "whittle" away the metal using complete strokes versus leaving the bit in one place on the metal and cutting a notch. Blend that gasket match back into the head about 1" or so. When it looks good, then come in with the sanding rolls to clean up/smooth out. Leave the walls a little on the rough side - not shiny mirror polished.

I used a cheapo inside Snap Gauge kit I got from Harbor Freight to equalize all the ports at the pushrod bulge just inside the intake port. You can see in the photos that this is a "pinch point" as it narrows. This is really your port size, not the opened up to the gasket size. You can go crazy and grind right through the pushrod bulge and then use brass tubes/epoxy to come back in and insert the tubes to seal the pushrods off. This maximizes that "pinch point", but I did not go that far. This pinch point is where additional flow comes from and I may have gotten more flow out of my heads, but did not want to go extreme. I did grind away a little, and then adjusted my snap gauge width and used that width as my measure to get all the ports at the pushrod bulge all the same width.

I did not do any metal removing down into the ports like radius' or the port roof as some do to improve flow. You need templates to do this, gotta really know what you are doing, and it can thin the walls next to the water jacket ad you don't always know how much material there is. So this was simply polish up with sanding rolls.

I did open up the port throats using the 3 cut down valve sizes in the Jim Hand book. HOWEVER, I believe I used the noted diameters, but in Pete McCarthy's video, you actually want a template that has narrowed sides for a more "oval" template that is said to increase the air flow around the valve a little better (also recommended by David Vizard)- ie 1.60" diameter with the sides measuring 1.50". I had extra valves so I made up some valves instead of using the paper circular templates also shown in his book you can use. I spray painted the bowls/chamber white so I could see my grinding work - made it easier to see my work and keep things even and blended. I carefully opened up the throats being very careful not to accidentally nick on the valve seats. I ground the valve guides in the bowl to make the edges a little smoother but did not cut them down or eliminate them as some I have seen do. Then smoothed/blended it all up with the sanding rolls.

Did not do much on the exhaust ports other than gasket match, grind away the casting bumps, blend and polish.

Inside the chambers I followed Jim Hand's book. Layed back the "ski jump" a little by whittling it away and blending. Look at my pics and you can see on the heads when I took them off, the area at the intake valve where the air flow has left that "ski jump" clean. I have read this is needed for turbulence to keep the fuel mixed and not falling out of suspension. OK, I removed it per Jim Hand. LOL That's all I did with the chamber. Did not try to use a head gasket and grind the chamber to the edges or any other grinding, just the "ski jump" and then polished it. I figure that is where I lost 2 CC's.

Additionally, I removed any sharp edges/casting flash and check the oil return holes for casting - pic with the white arrows. I opened up the tops of the pushrod holes with the carbide bit for use with the 1.65 rocker arms so they don't hit the pushrods. Did this by eye and will verify that my pushrods clear once the head is set on the block to get my pushrod lengths. I may have to do more clearancing if I did not grind enough, but think I did.

I spent a good amount of time getting all this done - slow as she goes, no rushing anything.

Once done, then the heads went to the machine shop with my new Ferrera RA IV length valves. My machinist purchased new springs/retainers/valve locks which he said was good for .600" lift. Installed bronze valve guides, cut down the valve guides for the Viton valve seals.


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## ponchonlefty (8 mo ago)

PontiacJim said:


> First thing, have your heads hot tanked and magnafluxed for cracks before doing any work. My description below is from what I did as an "amateur" as I do not port heads for a living. I have cleaned up several heads in the past to improve them, but not go for any kind of maximum flow and never had a set flowed on a machine until this set. I know enough to be dangerous and my goal was to simply clean up the heads and get a little more than stock flow - which I did. In theory, the extra flow should support the estimated 425-450HP I hope to have while keeping port velocity high for a nice responding engine.
> 
> Jim Hand's book was my guide in prepping the heads and enlarging the port throats. BUT, if you want a really good video showing all this, the tools, the templates, and testing. Purchase the *Performance Porting* video from Pete McCarthy. Well worth the price.
> 
> ...


thank you, this is very helpful. i have a magnafluxer and a valve grinding machine. i was a machinist many years ago.i have a set of 6x-8 to practice on. i need to get a few more tools and time to do it.you guys are awesome so much knowledge.


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## PontiacJim (Dec 29, 2012)

ponchonlefty said:


> thank you, this is very helpful. i have a magnafluxer and a valve grinding machine. i was a machinist many years ago.i have a set of 6x-8 to practice on. i need to get a few more tools and time to do it.you guys are awesome so much knowledge.


It's all part of trying to improve performance even if sometimes what we do is only that slight increase in HP. We do it because we enjoy it and can say we did it. It doesn't always have to be done professionally, just done to the best of our knowledge and abilities. Sometimes that is worth more than what you would pay a professional.

Just take your time.


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## ponchonlefty (8 mo ago)

PontiacJim said:


> It's all part of trying to improve performance even if sometimes what we do is only that slight increase in HP. We do it because we enjoy it and can say we did it. It doesn't always have to be done professionally, just done to the best of our knowledge and abilities. Sometimes that is worth more than what you would pay a professional.
> 
> Just take your time.


yes, for me its worth it. i like fixing things myself.i was a machinist so im not scared to cut steel. measuring and going slow is part of it. we used to say a machinist in a hurry is about to make a mistake. its just fun for me.a challenge to conquer.


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## smcbride (23 d ago)

BearGFR said:


> My 69 came from the factory with #62 heads, and it was just a 'garden variety' YS coded 400. I think that RAIII heads carried different numbers, but honestly pretty much all the D-port, large valve, screw in stud heads all had the same ports and were essentially the same head. Differences, if there were any at all, between 62's and RAIII's would have been extremely small.
> 
> Bear


I think it is a tracking mechanism mostly. Probably where it was actually cast in some cases. It was for quality control of defect machining tool batches and metal cast quality. I kind of remember that automatic transmission and a manual transmission heads had a +/-1 difference in the numbers. It might be something on the head was threaded for the automatic if I remember correctly. Not sure if it was a sensor or heat tube. All the vacuum lines come off the manifold. A lot of cars are like this. For example, my 3SGTE motor for my MR2 has exhaust threading for either a 5 bolt or 7 bolt manifold. Popular mod is to go ahead and thread out the other 2 holes for aftermarket turbo manifolds.


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