318 pistons

Off hand, I don't know, but I would look at a set of Federal Mougal pistons to get what you want.

If you can't find the ratio your looking for, the KB's for the teen @ zero deck can be used. Just use a thicker gasket.

OK, with a zero deck piston and a 72 cc head (Ave 360 chamber/open style), MP .028 gasket thick and 4.180 bore size.. You get a 9.33 - 1

If the bore size is 4.00 inch and everything else stays the same, it rises to 9.38 - 1.

65cc head = 10.21 - 1.

Thicken gasket to .054 (Fel-Pro has one like this, not sure of bore size though.) everything else stays the same, you get 9.56 - 1.