Originally Posted by TonyJ
OK, I sent my 113 heads out to Robbie McCay, he did a port job and put in new valves. Took .030 off the deck, and Im running ..030 head gaskets. (Stock was .048 and had, according to S&S 10.1 compression.) 0 piston deck height.
Im running the S&S640 cam, and I figured that with taking .030 off the heads and .018 out in gasket, my CR should be about 10.8.
When I do a ccp test I get 170-175PSI, is this about right?
I cant directly answer your question, but i will tell you this, psi in the cylinder doesnt directly correlate to compression ration, simply because of camshaft profiles, duration, overlap and all that stuff, my buddys 12.5 to 1 468 only has 200 psi cranking compression, because of the huge overlap. hope that helps.