[Carnut427]

As vettestr mentioned, if the deck hasn't been milled, most small block pistons are .020 or so down in the bore. When you add a .041 thick head gasket, you loose too much squish (or quench, whichever you want to call it). To remedy this, use a Part # FEL1094 Shim-type head gasket, .015 in. Thick, 4.100 in Bore, for use with Iron or Aluminum Heads. Can not be used on 400ci engines. Embossed shim with precision coating does not cause any brinneling on aluminum heads. 1 gasket per package. Price: $18.95 . Using these gaskets will give you the disirable .035-.040 squish, which allows you to run a little higher compression without detonation. The squish is the air/fuel mix being squeezed out of the area where the flat area of the head & piston come towards each other. This squish creates turbulence in the combustion chamber, cooling off hot spots and keeping the fuel & air correctly mixed. You then choose the head cc to match your piston to give you the compression you want. THEN choose a cam that will give you a DCR of around 8:1 for iron heads and up to 8.4:1 for aluminum heads. Do all this correctly and you've got yourself a screamer, no matter what brand it is.
Good Luck,

Dan