Cylinder Heads Stock versas Aluminum - Pontiac GTO Forum
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post #1 of 5 (permalink) Old 03-09-2019, 12:56 PM Thread Starter
 
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Cylinder Heads Stock versas Aluminum

Hello everyone, I am still learning about Pontiacs and will admit they are not like Chevys and Fords.

I am building a Pontiac 400 for my 67 GTO. Based on what I've read in this forum there are some very good heads from Pontiac. I have a set with casting number 12, X6 and an 8 stamped on the left boss or nub. They have screw in studs with 2.11 intake valves. Based on information available this should produce around 350HP. My objective for the car is to have decent horse power to enjoy the car. There are no plans to race the car.
My questions is whether you would stick with these heads or go with an aluminum set.

Also any suggestion on a cam?

Thanks for any opinions,
Finn

Last edited by Finn Engsig; 03-09-2019 at 01:07 PM.
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post #2 of 5 (permalink) Old 03-09-2019, 01:16 PM
 
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Got the same heads in my 68 gto. You will need to get CR down to mid 9 for pump gas. ( if you got stock piston your closer to 10.5 to one with those 12 heads. My 12 heads cc at 72 so for me I had my shop dish 14 cc out of each piston . He charged me 75 dollars for all 8 piston ( I used forged TRW) not bad. This got me to 9..5 . I got 360 hp and 455 lbs of torque and run 89 gas but it will run on 87. If you pm your email I will send you my build sheet and my dyno sheet. This engine is a blast to drive . So to answer your question I love the iron heads and I love to save money . Doug
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post #3 of 5 (permalink) Old 03-09-2019, 01:22 PM Thread Starter
 
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Thanks for the quick reply Doug and yes that sounds exactly what I'm looking for.
I really apricate any information you would share with me. Thanks again Doug.

My email is [email protected]
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post #4 of 5 (permalink) Old 03-09-2019, 02:24 PM
 
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If you decide not to use the #12 heads, you can probably get somewhere between 300 & 350hp, with the 6x-8 heads. Better to have some shaved off to get the CR up closer to 9:1. They are said to have aprox 100cc chambers, from the factory. Best cam for a 6x-8 head street 400 might be the Lunati Voodoo 262. But certainly not the only decent choice.

Voodoo Hydraulic Flat Tappet Cam - Pontiac V8 262/268 - Lunati Power

Here's a forged piston 6X 400 build, just for an example. Probably has 6x-4 heads tho, with less than 90cc chambers.

400 Long Block

Or, you can go with a 455 or 400 block stroker, 6x-8 heads, & easily get 400hp/500 torque.

455 Long Block

455 Short Block

No, I haven't bought an engine from Len Williams. But, I have heard good things about him. And, I do have a 6x-8 head 455 in my LOW budget bracket Bird. I put a Summit 2802 cam in it, along with Jegs lifters, to save some $$.

If you go with a 400 & the #12 heads, the Summit 2801 cam might be a good choice. But, lots of street-only 400 guys go with an 068 clone, such as the Melling SPC-7. It has barely over .400 lift, and doesn't seem to cause any of the problems that some higher lift cams & stronger valve springs cause.

If your budget will stand it, some 74cc KRE D-ports, or Edelbrock 72cc D-ports will make a good street 400. Can use Speed Pro forged flat top pistons. 10.5 CR is OK with alum heads. Don't need any porting. They flow better than iron heads, out of the box.

Kauffman Racing Equipment

https://butlerperformance.com/i-2445...tegory:1287735

Last edited by bigD; 03-09-2019 at 02:35 PM.
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post #5 of 5 (permalink) Old 03-09-2019, 03:00 PM Thread Starter
 
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Thanks bigD, you gave me some good information with links included. The cam you suggested is more what I'm looking for as I want to enjoy driving the car.

Thanks Finn
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