head swap

[The Frin]

Hey guy,new to the forum and love it.
I just pick up a 71 440 out of a c body for my 67 satillite and was going to leave the bottom end stock and swaping on a set of 915 heads to bump the comp.up. Stock she's at about 8.8 to1 with open chambers on it. just trying to figure out a basic ratio it will be with the closed chambers on it. Then I can choose my cam and intake.
346 heads on it now with I think 80cc (havent pulled them off yet to check) and my 915's are at 73cc.

 

[Cranky]

Do a check on those heads. All of the ones I've checked run right at 90cc for open chamber and 80 for the closed for stock untouched heads. The book goes by what's allowed by the NHRA back in the day and isn't right.

 

[Meep-Meep]

I checked my 915's and they came in right at 79.5 cc's. Make sure you get hard exhaust seats put in. I also measure the difference between a compressed comp head gasket (Fel Pro) and a compressed steel shim and got .4 cc difference. You can net almost one full point of CR using closed chambers and steel shims and that is a difference you will notice.