installing #16 heads on a 1977 400 - High Performance Pontiac Forums at High Performance Pontiac Magazine High Performance Pontiac

installing #16 heads on a 1977 400

  
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installing #16 heads on a 1977 400

 
fred8 fred8
New User | Posts: 13 | Joined: 06/09
Posted: 06/27/09
05:24 AM

Hello, I'm doing my first real real rebuild on a pontiac. Its my sons car its a 1977 trans am with a stock 400. We wanted to boost the hps so we boght some #16 heads rebuilt from a 68 400, we also got a comp cam xe262h the engine also has headers and a edelbrock intake with stock Q-jet. We want to install these soon but after reading some articles I'm woundering if this is a good set up. The 1977 stock cr is 7.6 , will the #16 heads make the cr too high? Also does anyone have any tips on installing the heads and cam.I'M new to the site, Thanks for any help.  

 
Pontiacman8 Pontiacman8
Guru | Posts: 1398 | Joined: 02/08
Posted: 06/27/09
08:16 AM

The #16 heads have 72cc chambers and will give you a 10:1CR with flat top pistons and that is too high for pump gas 9.5:1cr is the limit with pump gas.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

 
fred8 fred8
New User | Posts: 13 | Joined: 06/09
Posted: 06/27/09
08:48 AM

Thanks for the reply, can it run good on 93 octane and is there anything I can do to get the cr down to 9.5:1. thanks  

 
Pontiacman8 Pontiacman8
Guru | Posts: 1398 | Joined: 02/08
Posted: 06/27/09
09:16 AM

Ya you can have a good reputable machine shop open up the combustion chambers to lower the CR. They will need to open them up to 76-78CC

With 9-9.5:1CR you will have to run 93 octane.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

 
fred8 fred8
New User | Posts: 13 | Joined: 06/09
Posted: 06/27/09
11:03 AM

ok thanks for the infro  

 
Pontiacman8 Pontiacman8
Guru | Posts: 1398 | Joined: 02/08
Posted: 06/27/09
11:42 AM

Your welcome.
Anything else just ask.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

 
barneyformula barneyformula
Guru | Posts: 966 | Joined: 01/07
Posted: 06/27/09
08:26 PM

The other option is dished pistons, obviously not just a bolt-on but something to consider if rebuilding the whole engine.
Steve  
Trying to help... 'cause we don't all have to learn the hard way!

 
Pontiacman8 Pontiacman8
Guru | Posts: 1398 | Joined: 02/08
Posted: 06/28/09
05:23 AM

Ya but they will most likely have to be custom ordered which will come at a custom price. In the past I have been only able to get flat top pistons for the 326 pontiac engine.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

 
barneyformula barneyformula
Guru | Posts: 966 | Joined: 01/07
Posted: 06/28/09
06:57 AM

Wrong post, Pontiacman8 this guy has a 77 TA with a 400. Lol!
Steve  
Trying to help... 'cause we don't all have to learn the hard way!

 
Pontiacman8 Pontiacman8
Guru | Posts: 1398 | Joined: 02/08
Posted: 06/28/09
07:32 AM

Yep! your right my mistake sorry about that got the post mixed up or it was that I have the 326 that i"m building right now on my mind to much.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

 
fred8 fred8
New User | Posts: 13 | Joined: 06/09
Posted: 06/29/09
12:44 PM

Thanks for all the help guys I have a few more questions would I use Spark plugs and pushrods for a 1977 400 or 1968 400 ho and should I plug the exhaust crossover I have electric choke. Once again thanks for all the help.  

 
Pontiacman8 Pontiacman8
Guru | Posts: 1398 | Joined: 02/08
Posted: 06/29/09
12:55 PM

No problem.
The push rods are the same and I would go with the plugs for a 1968 or just ask for AC delco # R45s plugs but it should not be a big difference.
Yes I would plug the heat cross over if it is not needed.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

 
fred8 fred8
New User | Posts: 13 | Joined: 06/09
Posted: 06/29/09
01:03 PM

once again thanks for the infro.  

 
Pontiacman8 Pontiacman8
Guru | Posts: 1398 | Joined: 02/08
Posted: 06/29/09
01:41 PM

No problem,
Fred8 how about posting some pictures of that trans am in the readers ride section so we can see it.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

 

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