Whats my compression ratio?

[turbowrenchhead]

I had around 8.5 to 1 with .042 thick head gaskets. I could only run 12 psi of boost with 93 octane. I put in a set of .078 thick head gaskets. There is a huge difference in power, at least a 50hp or so less. I can't turn up the boost yet because of oil being pushed out of the oil pan gasket/silcone. Does anyone know how to caculate the cr with the difference in thickness of the gaskets?

 

[getchasum]

need more info

Heads cc @ ???
bore ??? x 3.4
Swept x 641.84
Dish - ??? Piston
C-Chamber ???

Gasket @ .078 "GM Stock Composite"
Actual Deck height @ .????X 6.60

 

[CTX-SLPR]

I can do it if you can give me the approximate cc's of the heads, piston domes, how much down the bore the pistons are, and if you've decked the block any. Assuming something like my 4.1 going from a .042 gasket with 8.5 you should have about an 8.25 with .078 gaskets but I can do it a bit more precisely if you feed us the specs. I built an excel spreadsheet that calculates a bunch of engine stuff from hard dimentions.

Thanks,

 

[disco stu]

http://www.empirenet.com/pkelley2/crc.htm

 

[turbowrenchhead]

Talked to my old machine shop and they said it should drop about a point and a half, so I'm just about where I should be.