head gasket and deck question

If you have a zero deck piston with a small quench chamber head a .020 compressed gasket will get you a pile of ruble in a hurry. You should aim for about .038 piston to head clearance with steel connecting rods. A little less is OK but no more than .040 to keep the chamber active. Get the smallest chamber you can, you can't have too much compression in a race motor unless you plan on pressurizing it with a blower or turbo or hosing it to death with nitrous. 4cc's isn't much for valve reliefs either, I think mine on the small block measured about 7 or 8 and they provide very minimal clearance, larger would be better.

The correct way to measure compression ratio is the total area of the cylinder above the piston with the piston at BDC divided by the total area above the piston with the piston at TDC. You'll need to take into account the bore diameter of the gasket as well since it is always larger than the cylinder bore.

The correct formula looks like this:

chamber cc's + gasket cc's + deck clearance cc's (in your case 0) + (displacement x 2.0483 for an 8 cylinder) + valve pocket cc's

divided by

chamber cc's + gasket cc's + deck clearance cc's + valve pocket cc's

to obtain cc's for the head gasket the formula is

bore x bore x 12.87 x compressed thickness (remember this is the head gaskets bore, not the cylinders.

formula for figuring deck clearance for those of you without zero deck pistons

bore x bore x12.87 x depth of piston in block.