[lust4speed]

Originally Posted by TRADERMIKE 2012

Mike wants to know: Do I figure a total of 72 cc - 11 cc valve relief to get 61 cc in the "D"-Port Bath Tub.

You are going the wrong way with your math. You have to add all voids to get the final combustion volume. So using your numbers, 72cc plus 11cc plus area for the head gasket plus the distance the piston is down in the hole plus a few other smaller voids like the area around the piston circumference to the cylinder wall down to the top ring (the last one most don't worry about unless using a piston with a large chamfer).