# Intake for 64 GTO



## tguggino (Aug 31, 2013)

Looking for recommendations on improving intake flow on a 64 389 78XW engine. We are going to tear down the engine for rebuild. Don't want to go multi carb right now. 
Want to keep original heads and intake manifold. (Unless someone convinces otherwise) 
Plan on porting heads, modernizing valve train, pistons, adding a bit more cam and headers. Trying to figure out what to do for carb. We have the stock afb which is a bit anemic at 500cfm


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## rickm (Feb 8, 2012)

edelbrock makes carter afb style carbs with higher cfms, elec. choke n manual. however the fuel inlet is on the passenger side and has a nipple for neoprene fuel hose instead of the stock metal fuel line.


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## PontiacJim (Dec 29, 2012)

Sounds like a plan. Were you going to lower your compression ratio during your rebuild? Getting it around 9.0 - 9.5 seems to be the way to go unless you are running racing gas or additives. 

If you go ported/polished heads, bigger cam, headers, etc.., then I would think something like the 750 AFB by Edelbrock might work for you. I am not a Holley guy, so I can't chime in on a choice or fit. You may even need an adapter.

As rickm pointed out, there are differences as compared to your stock carb. Easy enough to overcome, but just make sure you minimize the amount of rubber line you use and make sure it is compatible with ethanol laced gas or it will rot the lines over time and you don't want a fire. Most rubber lines today are fine, but just be sure.


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## tguggino (Aug 31, 2013)

PontiaJim. We are going to target around 9:1. Have not picked pistons yet. Open to recommendations. 
Also, what do folks think about porting stock 64 heads? Our plan is to go fairly high end on valve train. (And in general) Looking for rock solid reliability as priority #1. My Dad will be driving it around northeastern Florida. 


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## PontiacJim (Dec 29, 2012)

The 1964 block/engine was the last year to use oiling through the heads/rocker arm studs, BUT I believe the GTO block already went to oiling through the pushrods - so confirm this with your machinist. This is important when switching to '65 and later heads.

1970 #64 open chamber heads? Good choice, 87cc, open chamber, bigger valves. You cannot use the '64 intake as differing bolt patterns.

9.0 to compression is about where you want it, so that is good. On pistons, the choices are many and a few emails to the guys who build Pontiac engines may be of help once you know what size you are going to need. Will your engine be .030", 040", or .060" over? Less is better because it gives you material left for another rebuild, but you can also sleeve an engine if ever needed -but this can become rather expensive. 

As I build my 455, my goal was to make the rotating assembly as light as possible. Less weight=less stress, faster revs, safer at higher RPM's. I weighed my factory cast pistons/pins & rods against my purchased forged pistons/pins & rods and was able to save 300 grams per piston/rod combo which is a substantial savings. I used the Keith Black ICONN forged pistons/pins. 

So my suggestion if buying individual parts is to try to watch the weights and you want to go forged pistons/rods. You also must be aware that the later open chamber 64 heads puts the valves at a different angle/position that the early 389 engine/pistons, so this has to be matched or at a minimum, the valve to piston clearance measured so there is no issues with valves coming too close to the piston. Pontiac Dude (Ken Keefer, Ken's Speed and Machine, Brooksville, FL) offers a deal on "custom" pistons for the Pontiac, that can be had with the valve reliefs in the correct position, and still use a 389 bore. You may want to email Ken's Speed and Machine.

For the #64 heads -Porting/polishing can be a benefit, but not always necessary. Matching the intake gasket to clean up the ports is OK. Cleaning up the ports by smoothing/deburring any rough castings is OK. You don't want to hog them out because you can ruin the flow -Pontiac knew what they were doing. You want a rough wall finish as opposed to smooth mirror finish which hurts atomization of the fuel. The best performance/dollar value is a good 3-angle valve job which will increase flow. I installed bronze valve guides. Use stainless steel valves. I went with the Ferrea "5000" series. The valves have differing lengths and should be matched with the cam you plan to use. I went with RA IV valves which are longer because I am going over .500" on the lift. You can still get great performance with a cam under .500" lift and most lifts over .470" are not needed -this is where longer duration makes up the difference, but longer duration can also move the power band/RPM's higher which may not be what you do more cruisin' on the street than top end blasts. The factory cams are great and the "068" is probably the best choice for a street engine ("067" was used for automatic cars), but there are numbers of cam grinds available. Use the 7/16" rocker studs to replace your factory 3/8" rocker studs. The stamped 1.5 rockers work great. If you go 1.65 rockers, you want to grind the pushrod hole in the head or there is a possibility the pushrod will hit the head on any big lift cam, but using 1.5 rockers and something like the"067" or "068" cam would save the extra work/expense.

So this is where you and your machinist have to get together and decide on pistons/cam/rocker arms/valves/springs. It is sorta like a package deal and everything has to be thought out and matched prior to building and plunking down your cash. No such thing as a cheap mistake -you're not running a Chevy. :smilielol:


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## tguggino (Aug 31, 2013)

Jim

Sorry for the confusion. We are looking to keep the 1964 GTO heads. I think they have a 68cc chamber. If it is not worth working on these heads we will leave stock and switch. The car has the original engine so we are looking to keep "stockish" parts and appearance.
Since it is a partnership with my Dad, we are debating the best way to build the engine. I am in favor of keeping taking it down to the bare block, boring .40 or so over, working the heads, putting in a hotter cam and some nice headers. Also, modernize whatever we can. He is going to drive it around, thus we need good reliability vs. massive power. Keeping it Pontiac is a forgone conclusion. Just need the make sure he never gets stuck. I will never hear the end of it.


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## PontiacJim (Dec 29, 2012)

No problem.:thumbsup: You should have the "716" heads, 68-70cc's. Always magnaflux them for cracks before doing any work. Much of the same stuff applies, gasket match the intake ports, de-burr/clean up the ports, 3 angle valve job. The heads have pressed in studs, so if you keep them, you don't want to go too big a cam over stock and get too high on spring pressures. 

My books say that the '64 GTO used the "009" cam which is identical to the later 1965-1976 "067" cam, both with .406" lift -just to give you an idea on your cam's lift. The "068" HO cam has the same .406" lift, but intake duration of 288 vs 273(yours) and exhaust duration of 302 vs 289(yours). So the "068" would be a hotter cam and still have the .406" lift as your cam so as not to create any problems with your press-in studs.


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## Pinion head (Jan 3, 2015)

Ported 716's have been a favorite cast iron head for '61-64 Catalina builds with 4" stroke engines (434-451) for quite some time. Over the years, have sold several single core 716's along with a pair of 716's, and most made it under the hood of '61 Cats and Venturas. With work from the right experienced shop, head flow can be seriously increased while keeping port velocity high. I'd ck with Dave @ SD Performance, SD has a handle on working the early heads.

SD Performance- Pontiac Performance Specialists

Btw, if looking at used early (non screw-in stud) Dport heads that have been converted to screw in studs, make sure that you have the opportunity to remove the rocker studs and have the heads magnafluxed. i would demand a guarantee, that heads are not cracked, if was in the buying mode for such heads.


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## tguggino (Aug 31, 2013)

Thanks Guys. Are there known issues with the 716 heads cracking? Anything else we should consider with the 716 heads?


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## PontiacJim (Dec 29, 2012)

tguggino said:


> Thanks Guys. Are there known issues with the 716 heads cracking? Anything else we should consider with the 716 heads?


Not really, just precautionary. What Pinion head is talking about is when a shop converts the press-in studs to screw in 7/16" studs. The pedestals have to be machined flat and then the studs are larger so fitting them into the pedestals means the holes get opened up and the pedestal wall become thinner. The holes have to be opened up with a little bit of precision and even then it doesn't mean each hole is perfectly centered or the casting has and equal amount of material on each one. Add a high lift cam putting additional side loading on the rocker arm stud and you can see why the pedestal may crack or break -so these conversions need to be magnafluxed for cracks. You won't have any problems as yours are stock and you should be keeping yours stock, but you want to still have them checked for cracks rather than miss something, invest $$$, and find out after the fact. 

To keep press-in studs from pulling out on many of the hi-performance engines of the day, the factory would "pin" the stud by drilling right through the pedestal and rocker stud and then insert a roll pin to secure it. This was also done by machine shop/engine builders on hi-performance engines as well.


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## tguggino (Aug 31, 2013)

Awesome info. Is it required and/or advisable to convert the press-in studs to screw-in studs if we want to modernize the valve train. Lets say we use the "068" type cam and an all roller set up. Better question may be, when is it required to convert? 
Side-bar question; Since we plan on updating the "guts" of the engine, does it make sense to go with a stroker kit, or does that put extra stress on the 51 year old block & heads. Should we stick to a clean bore and standard stroke?


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## Pinion head (Jan 3, 2015)

Proper installatation of screw in studs, there should be no cracks in the machined seat area for the rocker studs. I have a feeling the 716's my buddy currently has got the "country boy" treatment years ago, then the cracks did not show up till the screw in studs were removed last Fall.

As far as fitting a stroker crank, it's all boils down to what you want to do with the car. Easier to make a lot of midrange torque with more cubes. Dave @ SD has a CNC program for porting the '67-72 intakes so they flow better than a tall Performer RPM. With the increased headflow, your going to need more intake flow than totally stock AFB intake and carb. Not sure that he has such a program for the AFB style factory intakes. Fellows I've dealt with that have used ported 716's, did so on 4" stroke engines and did so with tripowers and repro bathtub dual 4 intakes. Fairly healthy Pontiacs that were not as light as a barebones '64 GTO. Not confined by engine class rules (like I am with my '71 HO Pure Stock builds), i don't see the sense to building a 389, which with well ported heads and cam selection should make all its power up top, most likely to 6500 rpm, it will be wasted on the street and would need extremely low gears at the track. Instead, a well thought out stroked engine combination should be able to make 400/500+ gross HP/torque, and be able to do so at 9.2-1 compression on pump gas and be able to use moderate gearing to max effort both on the street and at the track.


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## tguggino (Aug 31, 2013)

We are considering a single 750 CFM or dual 500 CFM. We have a dual quad offy manifold as an option. (just because it is cool) Ideally we would like to stick with single 750 CFM, upgraded internal parts and a reliable street motor. If the stroker kits does not have any adverse affect on the engine, it would be great to have the extra cubes. Our goal is reliability, not all out power.


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## Pinion head (Jan 3, 2015)

There should be no loss of reliability with a 4" stroke 3" main crank. If you're going to go that route, I'd watch for a quality crank forging, versus a chinese cast stroker crank, then select quality forged pistons with the right cc reliefs to lower the CR to at least 9.3-1. if that C/R can't be accomplished, it's time to think of running a set of larger chamber '65+ heads and intake, or a pair of alum heads.


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## tguggino (Aug 31, 2013)

I was looking into Butler performance. I purchased a book about rebuilding Pontiac engines and they came highly recommended. Actually spoke with Jim Butler for about 20 minutes.


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## oldskool (Apr 26, 2015)

tguggino said:


> I was looking into Butler performance. I purchased a book about rebuilding Pontiac engines and they came highly recommended. Actually spoke with Jim Butler for about 20 minutes.


The Butler name is one of the biggest in the Pontiac world right now. Therefore they can get by with higher prices. They do quality work. If you can afford a Butler engine, then by all means buy one.

If not, there are other, lesser known guys, who can build a good engine, for less. Some say you get what you pay for. But some guys just can't spend 10 grand on a mild street engine. 

I'd consider, just keeping all your original engine parts for future use or sale, and building or buying a later model engine, for daily driving. That way you don't have to worry about how much to bore, hard to find parts, heads that need screw-in studs added, etc, etc. You can use a '71-'75 casting #481988 400 block, and it will fit early or late 2 or 3 bolt mounts. 

You can build a real mild 400 block, 4.25" stroker, with cheap unported 6x-8 heads, a good quality built Q-jet carb, a reasonable cam, and have 400hp and near 500ft lbs of torque, for around $5000. And you won't have to turn high rpm. It'll make power from an idle to 5000rpm--right where you need it on the street.

Hey, it's just food for thought. But it will simplify things.


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## tguggino (Aug 31, 2013)

Cool. Don't have the funds for a full butler engine. Just thinking about their rotating assembly. 


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## PontiacJim (Dec 29, 2012)

tguggino said:


> Cool. Don't have the funds for a full butler engine. Just thinking about their rotating assembly.
> 
> 
> Sent from AutoGuide.com Free App


The Butler rotating assembly is the best value. You get all new parts and it is balanced. The price is right at $1,950. NOTE that their are 2 advantages with this choice. 1.) you can get dished pistons in the cc's that you will need to achieve the 9.0 compression ratio. 2.) you can get custom bore sizes - which means if you can go .020" over rather than the typically manufactured .030" pistons, you have that many more times to bore the block out again should the need arise. So let your machinist know that you can get custom sized pistons and see what the minimum is that he can do to clean up your block.

Adding a longer stroke will generate more torque and torque is what a Pontiac is designed for. Forged pistons/rods/new crank means you can safely increase RPM's, but my guess would be that your heads, and their air flow, will be the limiting factor with regards to RPM's. However, even at the lower RPM's this engine might see (let's just use 5,000 RPM's), the amount of increased torque through the entire usable RPM band will be greater than the stock 389 now in your car. This equals more pulling power (providing you get good traction) and that means a faster accelerating car -all things equal.

So the stroker kit allows you to take advantage of a milder build (ie camshaft) and enhance it with the addition cubes to make a very streetable car versus taking the 389 and having to add a bigger/radical cam to get the same results with the 389 being less streetable or even balky to cruise in.

That said, do as I recommended with your "716" heads, don't go with screw-in studs as you won't need them, use the "068" cam which has the same lift as your original cam(so you know you won't have any issues with the stock rocker studs) with its hotter duration numbers (which will become somewhat toned down due to the bigger cubes), use factory stamped steel 1.5 rocker arms (use the available aftermarket rockers) and not the roller rockers. See if your "716" heads have "pushrod guide plates." I read that they did not and this is needed for roller rocker as you don't want them going sideways on you, plus the cost is not worth the justification short of you simply wanting to say you have roller rockers.

Personally, I'd go with the Offenhauser 2x4 and 2 500CFM's as this would be a period correct add-on for your car and give you the extra CFM's your engine will appreciate.

Again, if it were me, I would email Butler about your interest in the 389 stroker kit for a 9.0 compression street driven car and then provide him with your build to compliment the stroker kit; "716" heads, mild porting, SS valves, 3-angle valve job, factory press-in studs, 1.5 rockers, "068" cam, Offenhauser 2x4 w/500CFM AFB's, RA exhaust manifolds, and then ask his opinion of your build and if there might be any changes he would suggest as you want to match all your parts prior to purchase/rebuild. The more info you give him, the better idea he will have on your build and can suggest changes -these guys build Pontiacs and its all they do, so they know Pontiacs and you won't be guessing about your build.:thumbsup:


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## oldskool (Apr 26, 2015)

*Options*

If you decide not to build with your block and heads, the Butler rotating assembly is only $1550. That gives you $400 to buy a good 400 block. 6x-8 heads are usually about $200 or less. They have hardened valve seats, screw-in studs, and guideplates. With these, you can run flat top pistons, and a cam with more lift than the 068.

http://www.jbp-pontiac.com/products/engines_assemblies/rotating_assemblies.html#461_467

What I'm saying is that, for the same money, or maybe even a bit less, you can build a bigger, better engine, and will still have all your 389 parts. And, there's another big decision involved here. You must find a GOOD machine shop where they know Pontiac engines, to do your machine work. A Chevy shop can really make a mess of a Pontiac engine build. I learned this the hard way. 

Just to give you an idea of what a decent price is for a long stroke engine with 6x heads, similar to what I have described, here's a 455 crate engine with Eagle rods and pistons, for $4500 + shipping.

455 Long Block

Here's just a 400 block 4.25 stroke short block, with good pistons and H-beam rods, for $3200 + shipping. And these prices include the block. I'm thinking there's probably no way you can buy the parts and have a GOOD Pontiac machine shop build your engine for these prices. But I could be wrong. 

455 Short Block 

More food for thought.


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## tguggino (Aug 31, 2013)

This is truly amazing advice. Thank you. One quick question for PJ. Why not go with roller rockers and valve train components?


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## PontiacJim (Dec 29, 2012)

tguggino said:


> This is truly amazing advice. Thank you. One quick question for PJ. Why not go with roller rockers and valve train components?


More based on a personal note I suppose. I also look at everything based on budget versus advantage/disadvantage. The roller rockers come in a variation of types, from "inexpensive" to (my opinion) "expensive." Comparing prices as matched against the factory aftermarket stamped 1.5's, the 1.5's can be had for $91.97 http://www.summitracing.com/parts/cca-1251-16/applications/make/pontiac/year/1964 The roller tip rockers are $150.97 http://www.summitracing.com/parts/cca-1451-16/applications/make/pontiac/year/1964. (Personally, I can't think of any big HP factory muscle car that had roller rockers installed, and their were many big HP cars that were pushing HP number greater than what you are looking for.)

Next you begin to get into full rollers with roller tip & roller fulcrum and the price goes up depending on brand. What I do note on these full roller types is that it requires "polylocks" and to the best of my knowledge(and having no expertise here) your press-in studs might not be long enough to use "polylocks" with full rollers. Again, no expert on this as yours is a 1964(early) engine, but definitely something to inquire about if you go with the stock rocker arm studs.

The Comp roller tip rockers also mentions use with 7/16" studs and polylocks, so may not work for you. I have read that some roller tips can come apart, but my guess is they were not used as intended and some guy had a mega lift cam with super high spring rates and wanted to go cheap.

The Comp stamped 1.5's state "*Notes*: Designed to fit OEM stepped studs, 7/16 in. shaft with 3/8 in. threads" which is what you have now.

The Comp 1.5's are made very consistent so you will get a true 1.5 ratio where stock rockers are said to vary and some being 1.48 from what I have read. If you go with something like the "068" cam or some variation and keep the lift down, why invest extra dollars where it really isn't needed and save the extra $$$ to put somewhere else on your build?

Again, no expert on this, just a Pontiac enthusiast like you and many others, so your machinist or one of the many Pontiac engine building experts found on the web would most likely provide the advice you can bank on. I'm not saying you can't convert to screw-in 7/16" studs either, because you can and this may be a better route overall, but I would be darn sure I had an expert shop do it who knew the ins & outs of the early Pontiac heads such as yours. One goof at the machine shop, and you could be looking for another replacement head. You also don't want something that looks good and seemingly works only to have something break or crack on you later down the road. In building my own engine, like you, I did a lot of research and asked a ton of questions. In doing so, I put together a build I was comfortable with and on a budget I could afford. I added a few $ extra's that were not essential (like a gear drive), but it is what I wanted on my engine, and I don't plan on babying the gas pedal/trans/or tires.:thumbsup: If I blow it up, it'll be blown up in a blaze of tire smoke, and I'll re-build it again because I'm not going original and am not worried about breaking parts that don't have the same value as original numbers matching components. You had originally stated you wanted something with a little more power using the original block/heads and yet dependable. The more stock you keep things, I think the more dependable it may be in the long run for you/your Dad -just like it was when originally built by Pontiac.

You may even consider sending your heads out to one of the Pontiac builders if nothing more than installing the screw-in studs and then having your local guy do the porting/polishing/3-angle valve job, etc.. So you have options, its just a matter of what you choose to do and how you plan to go about it. I can't tell you how many times I have second guessed myself on the parts selection I have chosen in building my engine -still do sometimes. It really just boils down into just making a decision and hoping for the best outcome. You hope the engine runs like a raped ape and doesn't fall flat on its face!:yesnod: There is no magic bullet or one size fits all in the world of engine building. Just ask the question, "What is the best xxxxx?" and see how many different answers you get and what products are said to be the best only to have another say it is the worst!

PS: I'm using stamped rocker arms, but my 1972 7K3 heads came with factory screw-in studs and I replaced them with the ARP BB 7/16" studs so I can use the polylocks with the solid cam/lifters I went with.


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## oldskool (Apr 26, 2015)

Here's a little extra info that may help somebody down the line. You can use 3/8 polylocks on the stock bottle neck screw-in studs. That's what I used on most of my bracket engines. The rocker balls ride on the lower part of the stud, which is 7/16. That's why you don't see one rocker for bottle necks and another for 7/16. 

My bracket engines made thousands of passes with bottle neck, screw-in studs. Never broke one. As long as you don't run a big cam with high spring pressures, the screw-in bottle necks will work. If I remember correctly, the RA4 was one of the few engines that came with 7/16 studs. I ran the RA4 grind cam in several engines, using the bottle neck, screw-in studs. But we were only turning the 455's 5500 max, because of the stock cast rods. We shifted at 5000.

I did crack 1 stock rocker. But it may have been nearly a hundred thousand street miles, before I started racing it. They are quite durable. I'd always do a close visual inspection, before using them. You'll find some that are worn real thin, under the rocker ball. Some are already cracked. But some seem to have very little wear.

Also, I think the main reason to use the cheap roller tip rockers is to prevent wear on the the valve tips. But some say the tips don't actually roll, therefore do not help with valve tip wear. So there you have it. Using stock rockers, I have worn some valve tips down to the point that the rocker was almost hitting the retainers, requiring valve replacement. But if the rocker tip rolls instead of sliding back and forth, the wear on the valve tip will be less.


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## Pinion head (Jan 3, 2015)

No advantage to roller rockers in such a mild application. Most roller rockers take up extra space and require double stacking valve cover gaskets or running valve cover spacers. On two of my 455 HO builds, am limited due to rules to .424 valve lift and stock 1.5 stamped steel rockers. Threw together a test fixture with my mag base dial indicator to go through buckets of stamped steel rockers to find 16 that were closest to 1.5 ratio. Having used cheap stamped steel roller tip rockers like the Comp's with large cams, got rid of them, and went to Crowers on my 451.


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