360 compression ratio, Am I wasting my time?
And this can be done with the J heads I have now? I mean the 9.5 compression ratio?
Just like fishy, I did this, what I wrote, with J heads cc'd to 72cc's. The pistons were KB107+.030 that sat @ zero deck and a Fel-Pro gasket was used. I do not remember the part number to it, but it was .039 thick.
If you have a desk top dyno, or other ratio calculater, know that there is a 5cc valve relief in the piston. If you can not make this adjustment on the program for piston relief, you'll just need to add 5cc's to the chamber (Taken from the valve relief area) and gasket diameter.
I just opened up the Desk Top Dyno for the ratio calc.
The Fel-Pro @ .039 thick will yeild 9.63-1 and gasket @ .050 will yeild 9.39-1 .
Since I do not remember the diameter, I used 4.1. Typical Fel-Pro spec or close. But the change is minimal.
With my Edel. heads, 65cc chamber, the ratio went to 10.43 or right close to it. (4.04 gasket @ .039 thick)
Very good for pump gas and a sizeable cam.
Of course type of valve face can change this along with a head mill to clean up and true the surface.
