Compression Ration =
Cylinder vol. + clearance vol. + piston Comp. vol. + gasket vol. + chamber vol. divided by Clearance vol. + piston vol. + gasket vol. + chamber vol.
Apply this to our example of the Chevy 350 with the 3.48-inch stroke, 4.00-inch bore, 0.015-inch deck height, 0.038-inch head gasket with a 4.000-inch bore, 76cc heads, and 4.5cc dished pistons, and here’s what it looks like:
43.730 + 0.188 + 0.275 + 0.478 + 4.638 divided by 0.188 + 0.275 + 0.478 + 4.638 =8.84:1
480RWHP 450RWTQ 15psi @ 15* on 91 octane