# 400 motor with 16 or 62 big valve heads



## cij911 (Oct 25, 2017)

I currently have a 400 with 14 heads and the original tri power setup. I have a set of 16 heads from a 68 Firebird - big valves, screw in studs, and small chamber ~72 cc (need to get exact). I also have a set of 62 heads, but have been told the 16s flow better. I would also like to add a camshaft if swapping the heads. (My goal is to get the motor to 350+ hp with a nice broad power curve.) My concern is the compression ratio and 91 octane here in socal.

My questions are:
(1) Can I effectively lower the CR enough with a thick head gasket?

(2) Is there a popular camshaft that would not only make more power but also lower the CR? Any specific recommendations would be great!

(3) If options 1 & 2 won't be sufficient in lowering CR enough (to ~9.25:1), I guess I need to build the bottom end with dished pistons ?

Thanks


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## PontiacJim (Dec 29, 2012)

cij911 said:


> I currently have a 400 with 14 heads and the original tri power setup. I have a set of 16 heads from a 68 Firebird - big valves, screw in studs, and small chamber ~72 cc (need to get exact). I also have a set of 62 heads, but have been told the 16s flow better. I would also like to add a camshaft if swapping the heads. (My goal is to get the motor to 350+ hp with a nice broad power curve.) My concern is the compression ratio and 91 octane here in socal.
> 
> My questions are:
> (1) Can I effectively lower the CR enough with a thick head gasket?
> ...


All D-port heads with the big valves basically flow the same, so its your choice. Best improvements would be gasket match the intakes & 3-angle valve job. Add ARP 7/16" BB screw-in rocker arm studs and poly-locks.

Do not go with thicker head gaskets -band aide fix. Get the correct dished pistons to give you 9.0-9.3 compression. 

Cams with a nice broad power curve will be those like factory - 114 LSA. Narrower LSA will typically narrow the power curve, boost cylinder pressure, and are more "explosive" but run out of steam early.


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## cij911 (Oct 25, 2017)

PontiacJim said:


> All D-port heads with the big valves basically flow the same, so its your choice. Best improvements would be gasket match the intakes & 3-angle valve job. Add ARP 7/16" BB screw-in rocker arm studs and poly-locks.
> 
> Do not go with thicker head gaskets -band aide fix. Get the correct dished pistons to give you 9.0-9.3 compression.
> 
> Cams with a nice broad power curve will be those like factory - 114 LSA. Narrower LSA will typically narrow the power curve, boost cylinder pressure, and are more "explosive" but run out of steam early.


Jim, I am coming back to this as I have the car pretty much done now and running well. Fundamentally what I am struggling with is what to do with the motor. Currently the motor runs fine - no smoke on acceleration or engine braking, but just is not a monster. The motor appears to be out of a 1968 Catalina (400 with #14 heads) and according to Wallace Racing's site should have a ~8.6:1 CR. I don't have any pinging (that I can hear) using 91 octane and when I did a compression test on the motor the numbers were all low but consistent, so I suspect it is a low compression motor. From what I have read the Catalina had a small cam, although I haven't found details other than what apparent stock replacement cams advertise. Is there really a huge difference between 8.6:1 and 9:1 ?

Given that all D-port heads flow close to the same, why not just replace the HFT cam with a better suited cam for the tri power and displacement and see if I am happy with the power results? It sure seems better (financially), than buying a built motor and heads. Worst case scenario I blow the motor and have to buy the built motor anyway..... I am sure I am missing something....Thanks in advance


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## bigD (Jul 21, 2016)

"... why not just replace the HFT cam with a better suited cam for the tri power and displacement and see if I am happy with the power results?..."


If the heads have press-in studs, you are limited on cam choice. Anything bigger than an 068 clone, such as a Melling SPC-7, is a gamble. And, if the springs are original, you'd need new springs.

https://www.autozone.com/internal-engine/camshaft/melling-camshaft-spc-7/107135_705947_0

https://www.ebay.com/itm/Pontiac-V8...622848?hash=item4206e6aec0:g:LYAAAOSwmrlU0mJ9

From a performance standpoint, a 262 Voodoo would probably be best for your low CR 400, to meet your goal. But, with it's steeper ramps, more lift, & stronger springs needed, it would very likely pull some studs.

https://www.lunatipower.com/voodoo-hydraulic-flat-tappet-cam-pontiac-v8-262-268.html

https://www.summitracing.com/parts/...B9Chp31rr367fUkNe7-urGydO03YcQRoaAgLIEALw_wcB

Some have been lucky, using larger cams, with press-in studs. If I was gonna try to get by with a cam larger than the 068, I might try something like a Lunati 10510312. It has only .454 lift, and the ramps are not as steep as on a Voodoo. And I'd use the stock springs from Ebay, linked above. 

Cams like a 744 clone adds more duration, without adding lift more than the 068. But the 744 was designed for high CR engines. Actually the 068 was also used mostly in high CR engines. The only low CR engine the 068 came in was the 455HO, & the only low CR engine the 744 specs were used in was the SD455. 

https://www.ebay.com/itm/Engine-Camshaft-Stock-Melling-SPC-3-/292730769560

The Lunati version of the 744 has less duration @ .050 lift, but has more total lift, at .424, and a lower LSA of 110°.

https://www.lunatipower.com/factory-performance-hydraulic-flat-tappet-cam-pontiac-v8-301-313.html

If you wanna try .450 lift, here's a possibility. Should make more power in a low CR engine than the 068. But, the ramps don't appear to be quite as steep as the Voodoo ramps. 

https://www.summitracing.com/parts/hrs-410021-12/overview/make/pontiac


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## cij911 (Oct 25, 2017)

BigD - Thanks a ton for all the help. How would I know if I had press in studs. If I recall correctly they appeared to have nuts on the end. (Sorry for the noob question. I really know almost nothing about camshaft design or selection, rocker arms, and/or lifters.)


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## bigD (Jul 21, 2016)

"...How would I know if I had press in studs. If I recall correctly they appeared to have nuts on the end..."

Screw-in studs have a hex that holds the pushrod guide plate down. Press-in studs do not have a hex. The bottoms are smooth all the way into the head. The guide plates are held down by bolts.

Here's a pic of #11 heads with press-in studs. You can see the head of the bolts that hold the guide plates down. The 2nd pic shows how the screw-in stud hex holds the guide plate down.


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## cij911 (Oct 25, 2017)

OK, why not put my big valve #16 heads on with a nice HFT cam and run 50/50 e85/91 octane for an effective octane of ~98 octane ? From what I have read, e85 loves timing and runs cooler too.


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## bigD (Jul 21, 2016)

cij911 said:


> OK, why not put my big valve #16 heads on with a nice HFT cam and run 50/50 e85/91 octane for an effective octane of ~98 octane ? From what I have read, e85 loves timing and runs cooler too.


The carb must be modified to run E85. So, getting it calibrated correctly for running some mixture of E85 & pump gas might be difficult. If you want more octane, you can either mix in some race gas, or add Torco Accelerator octane booster. 

https://www.summitracing.com/parts/tic-f500010t?rrec=true


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## PontiacJim (Dec 29, 2012)

cij911 said:


> Jim, I am coming back to this as I have the car pretty much done now and running well. Fundamentally what I am struggling with is what to do with the motor. Currently the motor runs fine - no smoke on acceleration or engine braking, but just is not a monster. The motor appears to be out of a 1968 Catalina (400 with [URL=https://www.gtoforum.com/usertag.php?do=list&action=hash&hash=14]#14 [/URL] heads) and according to Wallace Racing's site should have a ~8.6:1 CR. I don't have any pinging (that I can hear) using 91 octane and when I did a compression test on the motor the numbers were all low but consistent, so I suspect it is a low compression motor. From what I have read the Catalina had a small cam, although I haven't found details other than what apparent stock replacement cams advertise. Is there really a huge difference between 8.6:1 and 9:1 ?
> 
> Given that all D-port heads flow close to the same, why not just replace the HFT cam with a better suited cam for the tri power and displacement and see if I am happy with the power results? It sure seems better (financially), than buying a built motor and heads. Worst case scenario I blow the motor and have to buy the built motor anyway..... I am sure I am missing something....Thanks in advance



The #14 heads are press-in studs & small valves. 8.6 compression can be worked with. The draw back will be the press-in studs which will limit your lift. You probably don't want to go more than .440" lift to be safe. Factory lift is .406" and the H-O blueprint manual says that coil bind can occur at .446". Obviously larger lift cams can be used, but changes are in order and you want to use your stock heads "as is."

To take advantage of the 8.6 compression ratio, you want to build up *Dynamic Compression*. This adds more cylinder pressure in loosely the same way a higher compression ratio does. The factory cam in your engine now is very mild - and 7.6 seconds for the 0-60MPH most likely reflects that. The valve overlap is at 47 degrees - not a very "hot" cam.

You can use the Wallace Dynamic Compression Calculator to get an idea of what it will take to raise the Dynamic Compression. However, this may require a custom ground cam. I did play around with a couple cams offered on line, but nothing really fit the bill with the limits of the stock heads.

I went with a Comp Cams XE cam on my previous 1972 400CI build with its stock 8.2 compression, maybe less with the aftermarket 8-eyebrow cast pistons I used. The heads were the 7K3 which had the big intakes and screw-in studs so I could use a high lift cam. The cam really made that engine perform - I was impressed. Ran on regular octane gas all day long.

The Comp Cams use a tighter 110 LSA vs the factory 113-116LSA. The tighter LSA can build more cylinder pressure. These cams have "explosive" power, but peak early as opposed to a factory grind that has a broader and more even power range for longer.

The XE series has steep ramps that throw the valve open faster, so be advised that heavier springs may be needed to keep the lifter on the cam lobe - depending on type of cam grind/series some companies offer.

That said, and in my opinion in keeping the stock heads and wanting to do just the cam/lifter swap, I would inquire about a custom ground cam that will build cylinder pressure (Dynamic Compression) to work with the 8.6 ratio you presently have.


So using the Dynamic Compression Calculator, and *as an example*, you see how the Intake closing point affects Dynamic (cylinder) pressure.

67 degrees - 6.75 ratio (yours now)
64 degrees - 6.90 ratio
60 degrees - 7.10 ratio

So this is why I say you may need a custom ground cam to maximize your combination using the stock #14 heads. I think I might give it a try and then start saving for the "new" engine. You may even like the new installed cam in your present engine and just go with that. :thumbsup:


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## cij911 (Oct 25, 2017)

bigD said:


> The carb must be modified to run E85. So, getting it calibrated correctly for running some mixture of E85 & pump gas might be difficult. If you want more octane, you can either mix in some race gas, or add Torco Accelerator octane booster.
> 
> https://www.summitracing.com/parts/tic-f500010t?rrec=true


I am struggling with what would need to be modified as the accelerator pump uses ethanol friendly rubber and all of the other bits are metal....Maybe you mean jetting needs to be increased?

I have read that some pumps and fuel lines need to be changed, but I suspect this is more internet myth. I have new fuel line which I believe to be ethanol friendly as well. The seals in the fuel pump (mechanical), I am not sure of.....Other than that, what am I missing??


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## cij911 (Oct 25, 2017)

PontiacJim said:


> The [URL=https://www.gtoforum.com/usertag.php?do=list&action=hash&hash=14]#14 [/URL] heads are press-in studs & small valves. 8.6 compression can be worked with. The draw back will be the press-in studs which will limit your lift. You probably don't want to go more than .440" lift to be safe. Factory lift is .406" and the H-O blueprint manual says that coil bind can occur at .446". Obviously larger lift cams can be used, but changes are in order and you want to use your stock heads "as is."
> 
> To take advantage of the 8.6 compression ratio, you want to build up *Dynamic Compression*. This adds more cylinder pressure in loosely the same way a higher compression ratio does. The factory cam in your engine now is very mild - and 7.6 seconds for the 0-60MPH most likely reflects that. The valve overlap is at 47 degrees - not a very "hot" cam.
> 
> ...


Jim, thanks a ton. Very informative. Rather than work the #14 heads and low compression, why not use my #16 heads + cam + a blend of 91 / e85 (race fuel combo)? Seems like the #16 head route would certainly get me past the 350 hp level and I would be happy with that (for now)....


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## Lemans guy (Oct 14, 2014)

Cj Lunatics will grind you a custom cam for $50 more than an off the shelf cam......call them they are near Memphis.

Jim and BigD can advise you and Lunati can cut it for you.....


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## bigD (Jul 21, 2016)

cij911 said:


> I am struggling with what would need to be modified as the accelerator pump uses ethanol friendly rubber and all of the other bits are metal....Maybe you mean jetting needs to be increased?
> 
> I have read that some pumps and fuel lines need to be changed, but I suspect this is more internet myth. I have new fuel line which I believe to be ethanol friendly as well. The seals in the fuel pump (mechanical), I am not sure of.....Other than that, what am I missing??


You can read all about E85 & E85 carbs, online.

https://www.hotrod.com/articles/ccrp-1211-e85-carburetor-conversions-tech-questions-ask-anything/

https://www.hotrod.com/articles/converting-from-gasoline-to-e85-for-the-street/

https://www.e85carbs.com/


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## bigD (Jul 21, 2016)

Lemans guy said:


> Cj Lunatics will grind you a custom cam for $50 more than an off the shelf cam......call them they are near Memphis.
> 
> Jim and BigD can advise you and Lunati can cut it for you.....


Yeah, I think most custom HFT cams will probably cost at least $200 or more shipped.

Most of the NHRA Stocker cams come from either Comp Cams or Bullet. Therefore, they have lots of experience grinding cams with low lift, but more duration than most shelf cams, with that same lift, will have. We ran a Lunati "Stocker" cam, back in '75. They were big into Stocker racing back then. But, somewhere along the way, they sorta backed out of Stocker racing. 

http://classracer.com/classforum/showpost.php?p=334595&postcount=2

Bullet Cams Master List

Now will a custom cam be worth the extra price, to you ? Nobody can possibly know the answer to that. My answer would probably be: Only if I knew for a fact that the custom cam was much better than any shelf cam I could have bought. In street apps, there are probably lots of similar cams that will provide very similar performance, with the difference only detectable by dyno or drag strip testing. For street driving, you probably can't tell much(if any) performance difference between similar cams.


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## PontiacJim (Dec 29, 2012)

cij911 said:


> Jim, thanks a ton. Very informative. Rather than work the #14 heads and low compression, why not use my #16 heads + cam + a blend of 91 / e85 (race fuel combo)? Seems like the #16 head route would certainly get me past the 350 hp level and I would be happy with that (for now)....


Sure, the #16 heads would be better, but if I were to go to all the trouble of tearing down the top end, then I would have them gone through and completely rebuilt. They will most likey cc out at 75 CC's. 

Always have a machine shop disassemble them and magnaflux for cracks. I recall you mentioned these in the past. The cost to rebuild the heads can get high if you go through them with all new parts. I posted my heads before on the forum and they ran about $1200 complete.

Obviously they can be done much cheaper as long as the valves can be reground and the tip at the stem are not too badly worn. I would do a 3-angle valve job which will help performance - but this may require new valves with the "meat" on them to do it.

Springs can be re-used as long as each is checked with a spring pressure gauge and they meet the requirements of what ever cam you select.

Your stock valve retainers, oil shields, and split locks can be reused.

I would go new valve guides. Don't knurl them. If anything, the shop can use a steel liner and them make sure they are toleranced per Pontiac specs - too tight and they can seize.

The next option is bronze guides along with the Viton valve seals, but this will mean some machining of the valve guides so they will work.

Use the ARP Big Block 7/16" rocker arm studs along with matching polylocks. I would not use the bottleneck screw-in studs from the #16 heads.

Gasket match the intake ports and clean them up with sanding rolls if you feel confident enough to do it. I use a high speed die grinder and carbide cutter to get most, and then follow up with a course grit sanding roll to finish and blend. You want a little rough versus smooth/mirror finish.

Buy new 1.5 stamped rocker arms. If you feel rich, you can go roller tip. The new stamped will work just fine and have a true 1.5 ratio vs the factory that seem to fall a little short of this.

You want to talk with your machine shop and give him an idea of the cam lift you want to use.

If you go high on the lift, you may want to install new RA IV valves as they are longer, and matching springs/retainers. This is what I went with - Ferrea stainless steel, bronze valve guides, Viton seals, and new springs & valve retainers.

With those heads, you will be back up around 10.25 or so compression. Could be a problem unless you go with an additive or perhaps straight E-85. I would not blend - and how you going to know how much to blend?

I would not use thicker head gaskets, this is a bandaide that still might give you problems.

Cam choice will be the opposite of the #14 heads - you may want to lower Dynamic Compression. *bigD *pointed out a few cams. Wider LSA and long durations can help, but then bottom end may suffer and power won't be really pulling hard until mid and upper mid-range RPM's. I have read that the Summit 2802 cam is a better choice for this. There is a YouTube Video with a GTO having this cam and no detonation on a 1967 GTO engine and 93 octane 



 But, you will need new springs.

Also, read the last post on this forum. https://forums.maxperformanceinc.com/forums/showthread.php?t=831437


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## Lemans guy (Oct 14, 2014)

Well said bigD,..as you and PJ both said in essence,....

the bottom line is tailoring it for what cj wants to get ,.....smart of him to get it all thought out and explored,....that way he will get it right.


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## cij911 (Oct 25, 2017)

BigD / Jim / Lemans Guy - Thanks so much for the information. I am learning a ton from you!! Thank you thank you thank you. I am trying to find a great Pontiac machine shop out here in SoCal. I was told to find Jerry Goodale, but I can't find him - he probably has retired. If you know of anyone out here in SoCal, please pass me their contact info.

I've been playing with ethanol gas (e85) blends for a while now and absolutely love the fuel for high compression and forced induction motors. As long as your are not running on the ragged edge, it is easy to run ~ 5 gallons of e85 and 12 gallons of 91 octane and effectively get ~e30 with a ~95 octane rating. This blend is very knock resistant, runs cool, and is not % wise ethanol that you generally need larger injectors and my guess is the jetting on my GTO would be fine (as my AFRs are in the mid 12's on the GTO).

Again thanks for the help!


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## cij911 (Oct 25, 2017)

OK I read more on the Torco additive and was skeptical. I will try to find the MSDS on it and see what it really has in it. That said, according to their literature 64 oz (2 bottles) should bring my ~ 20 gallons of 91 octane to ~102 octane . Seems like an easy (and not too expensive) solution to the high compression issue.


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## geeteeohguy (Feb 2, 2008)

Octane Supreme 130 by Kemco works great as well. Not cheap, but it's real TEL. And it works.


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## PontiacJim (Dec 29, 2012)

Cam selection? Check out the bottom of my post #11 on page 2, played around with my Dyno2000 engine program and came up with a strong cam: https://www.gtoforum.com/f170/cam-shaft-135243/index2.html#post889751


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## cij911 (Oct 25, 2017)

PontiacJim said:


> Cam selection? Check out the bottom of my post #11 on page 2, played around with my Dyno2000 engine program and came up with a strong cam: https://www.gtoforum.com/f170/cam-shaft-135243/index2.html#post889751


Jim, I saw the post originally and re-read a few times. I am not sure how this cam you have designed compares to off the shelf cams, are there a couple that are very close (I would imagine so). Only reason I ask, is that I assume cam designers have been through this process many times. A quick question for you though, I keep seeing big TQ numbers and relatively smaller HP numbers. I'd prefer to give up a bit of low end torque as it becomes more of a liability (impossible to put power to the ground, hard on the clutch, hard on the drivetrain) and get a bunch more top end power. E.g. a setup that had more like 400 ft lbs of torque and 550 hp would probably be faster, yet easy and fun to drive casually around town (below 4k rpm) and a hoot to drive like I do (up to 5500 rpm).

I am really getting excited about the idea of putting the heads on the car, selecting a cam, and running 91 octane + Torco. The GTO has the tri power and Doug headers and performance exhaust. My understanding is that I would want to decide on the cam and then determine rocker arms, etc. I would also like to minimize the need for headwork and keep lift at check to work with the motor (safety).

In terms of headwork, if I use the #16 heads, what should I do to them (controlling costs would be optimal)? They appear to have larger screw in studs with poly locks . I have no idea what springs or guides are in the car or whether the valve seats have been hardened. Do you know of any reputable shops you would recommend that won't charge an arm and a leg (almost worth getting aluminum heads)? 

Thanks again for your help.


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## bigD (Jul 21, 2016)

geeteeohguy said:


> Octane Supreme 130 by Kemco works great as well. Not cheap, but it's real TEL. And it works.


http://www.wildbillscorvette.com/OctaneSupreme01.htm

http://www.overkillgarage.com/octane-supreme.html

Yeah, I used "104 Real Lead", mixed with premium pump gas in my 455 bracket engines, back in the '70-'80's. Worked just fine.


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## bigD (Jul 21, 2016)

"...if I use the #16 heads, what should I do to them (controlling costs would be optimal)? They appear to have larger screw in studs with poly locks . I have no idea what springs or guides are in the car or whether the valve seats have been hardened..."


Well, that phrase "(controlling costs would be optimal)", severely limits what can be done. 

Since you say you wanna run a cam that will make good power to 5500 rpm, I'd recommend longer than stock Ferrea 5000 series SS valves, so you can use springs with a 1.70 installed height, so you'll have plenty of spring movement for a little over .500 lift. Another reason to go with new SS valves is that the factory valves are 2-piece, with a welded on tip. these have been known to come apart, dropping the lower part of the valve into the cyl, & causing major damage. I never personally broke a valve. 

Since you wanna get rid of most of your low rpm torque, I personally would run an 041 clone cam, such as a Melling SPC-8, WITH Rhoads lifters. There have been lots of guys who tried this cam in a 400, WITHOUT Rhoads lifters, who did not like it at all, because of the lack of low rpm torque. The Rhoads lifters restore some of the low end torque, below 3000 rpm, then act more like regular HFT lifters, above 3500 rpm. Since the 041 has only .469-.470 lift, with 1.5 rockers, you can probably get by with factory valves. I did. CC 988-16 springs are probably strong enuff to go 5500 rpm, with an 041 cam, with stock length valves. Cams with more than .470 lift may require stronger springs and/or longer valves with a taller installed height. 

This Crane might also work with stock valves & 988-16 springs. Should have slightly more low rpm torque, but slightly less power at 5500 rpm, than the SPC-8. 

https://www.summitracing.com/parts/...EixRF9nyONKDNg0eySh9VIuf6FmIYCaIaAusEEALw_wcB

"...larger screw in studs with poly locks..."

Yeah, looks like 7/16 studs, but the nuts are not poly-locks. They are just stock BBC type crimp nuts.

https://www.summitracing.com/parts/crn-99771-16/overview/

Here's what a poly-lock looks like. The nuts have allen-head lock screws that screw down inside them, to bottom out against the top of the rocker studs, to lock the nuts in place. Not sure why the word "poly" has come to be used for these nuts. 

https://www.summitracing.com/parts/cca-4606-16/overview/


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## cij911 (Oct 25, 2017)

BigD, I guess by control cost, I mean I don’t want to go crazy with iron heads as I can get aluminum performance for ~$2500.


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## bigD (Jul 21, 2016)

cij911 said:


> BigD, I guess by control cost, I mean I don’t want to go crazy with iron heads as I can get aluminum performance for ~$2500.


I've read that many have spent between $1000 & $1200, doing a set of Pontiac heads correctly, with SS valves, bronze guides, and all other required parts & labor. And that doesn't include any professional porting or gasket matching.

But, I suppose that beats the price of new alum heads.

And, I assume there are others who have built heads for less. My neighbor spent about $800 on his #62 heads, a couple of years back.


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## PontiacJim (Dec 29, 2012)

* cij911*: "a setup that had more like 400 ft lbs of torque and 550 hp would probably be faster, yet easy and fun to drive casually around town (below 4k rpm) and a hoot to drive like I do (up to 5500 rpm)."

*PJ*: Not realistic. Pontiac engines come with torque - that's their design. A 550HP can be had with a stroker engine, but be ready to shell out about $10,000. Check out these prices from KRE and note the 550HP build & price: Tin Indian Performance Pontiac Engine Builder Combinations

Check out Butler's engine - Whaaaaaat? Cast iron heads AND is that a hydraulic flat tappet cam?: https://butlerperformance.com/i-244...01-cu-in-long-block.html?ref=category:1267471

My guess would be getting 550HP from a 400CI engine would mean higher RPM's to go with all the aftermarket parts needed.

I don't think the '65 tri-power, or even the '66 version would be good for 550HP without some serious rework.

*bigD* has pointed out the "041" cam which could work with the Rhodes lifters. Here is a quick synopsis of the Jim Hand test cam session:

****Installed 041 cam with 1.5:1 rocker arms; E.T. fell off by 0.1 sec. and 1 mph. Car was all but impossible to drive on the street due to the rough idle and loss of low-end power.

****Installed 1.65:1 rocker arms on the 041. No performance gain, and even worse low-speed performance.

****Installed Rhoads variable (leakdown) lifters on the 041 with 1.65:1 rockers. Quarter-mile performance improved by .15 seconds and 1.5 mph over the 068 with 1.65:1 rockers. Idle quality was excellent, with high vacuum when the engine warmed up. Rhoads lifters cause a ticking noise similar to solid lifters.

****Due to the rpm limitations (5,500) of the 455 engine’s stock internal parts, and my desire to retain comfortable street driving, any new cam I tried would have to provide a smooth idle at 560-580 rpm in Drive with at least 12 inches of vacuum, and develop strong power from idle to 5,500 with the 3.55 gears in this 4,000+ lb. vehicle. The Rhoads lifters were used in all cam tests in order to maintain the 500 to 600-rpm idle capability with adequate vacuum to operate the power brakes.

****The 041 cam was designed for the highest level of power available from about 1,500 to about 5,800 rpm, which was the planned operating range of the 400 engines, for which this cam was originally designed. In our performance tests, the broad power range of this cam is obvious.

****For great street driving with some drag-strip work the 068 with 1.65:1 rockers provides outstanding performance with automatic equipped 455s, including air-conditioned vehicles. The 041 cam is suitable for both the 400- and 455-equipped cars with 4speed transmissions, with or without the Rhoads lifters. The 400 automatics perform well with the 068 and 1.5:1 rockers. 

****Both the 400 and 455 respond well to valve lifts of up to about .460″.

****All of the custom cams provided good performance at the strip, but in direct comparison, the 041 provided as good or better quarter-mile performance along with superior idle characteristics (with the Rhoads lifters). 

You can read the complete article here: Building a Strong Street Machine ? Part 5: Pontiac Camshafts | Dallas Area Pontiac Association


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## geeteeohguy (Feb 2, 2008)

The O.P stated that he wanted 350 HP with a broad power curve. Not too difficult to do with a moderately warmed-over 400. As for a 550 HP 400, Jim is correct: you would need a TON of airflow and lots of RPM. Easier to make that kind of power with a lot less strain and less exotic parts with a stroker crank boosting displacement to 461 CID. A mild stroker with more inches will live longer and be more user-friendly than a high strung, high winding smaller displacement engine making roughly the same HP (but with a BUNCH less torque). And torque is what moves cars.


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## cij911 (Oct 25, 2017)

PontiacJim said:


> ****For great street driving with some drag-strip work the 068 with 1.65:1 rockers provides outstanding performance with automatic equipped 455s, including air-conditioned vehicles. The 041 cam is suitable for both the 400- and 455-equipped cars with 4speed transmissions, with or without the Rhoads lifters. The 400 automatics perform well with the 068 and 1.5:1 rockers.
> 
> ****Both the 400 and 455 respond well to valve lifts of up to about .460″.
> 
> ...


Jim, thanks for the article.....Funny I keep reading about the 068 cam and how it appears to be a great performer and very streetable. The 041 sounds good too, but from the article there appeared to be very little difference between the 068 and the 041 from a performance standpoint.

I wonder if the 068 would work well in a lower compression setup (#14 heads ; 8.6:1).


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## geeteeohguy (Feb 2, 2008)

I think you would be fine. I'm running the 068 with about 9.3 CR in my '67 400.....power brakes, automatic, lazy 2.56 rear gear......it pulls hard. Especially on the highway at speed!


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