I am putting together a 340 stroker. The block will be .020 over with a 4" crank and 6.123 rods. I have ported eddy closed chamber heads that measure 66.4cc. I plan to use a .039" thick Felpro head gasket. I want the CR to be around 10.5:1 or a little more. I am going to use a cam that will bleed off some pressure so I think this would work well with pump gas in a relatively lite 69 barracuda notchback. It looks to me like all the stocked pistons for a 4" stroke SB are either flattops with about 5cc or dished with about 20cc. With a zero deck, the flattops will be about 11.6:1 and the dish pistons will be under 9.9:1. Has anybody put together a combo similar to this and found a piston that will get the compression up a bit?