how much would the compression drop by swapping the stock 64cc heads for some 76cc heads? how much can I gain back by using thin head gaskets? reason I'm asking is that one friend is selling some nice ported heads(76cc) and another friend needs new heads for his 91 Z28.

 

The CR will drop by a bout a point by going from 64 to 76cc heads. I dont hink you can mkae up that diff with gaskets

 

I once read on this site, that yes, you do lose at east a point (if not more) when going down that size. I also heard that you can nearly compensate with a gasket, not all the way but within a quarter point or so.

Just heresay though, take ot for what it's worth

BamaZ28

 

If the heads were surfaced as much as possible (along with the intake), and the thinnest head gaskets used, you might be able to come really close. The better flow of the heads might overcome some power that is lost. At least he could run 87 octane gas!!

 

thanks for the info. He is gonna wait and find some aluminum heads instead.

 

If he's interested. I have some L98 Vette heads complete w/o rockers, approx 60,000 miles, for $450 plus shipping. Just thought I would advertise...

BamaZ28

 

I'll let him know

 

He can get a set of Vortecs for around $450 and Scoggin Dickey has a TPI base that will fit these heads. they're not aluiminum, but they are supposed to be some of the best heads for the money. By the way, they have 60cc chambers.