Wrong pistons

As mentioned in another thread, I am building a 390 stroker, which was to include Hughes' Exclusive Icon stepped dish(-18cc) pistons. I was planning on using RHS/Indy heads from IMM with a skim to 60cc which would give 10.3 comp with a .040 gasket and zero deck.

I sourced the parts through my local engine builder who assured me he could get the Hughes' pistons from KB/Icon.

Well, they sent the wrong pistons (846 flat tops), he's balanced the whole assembly and even going to a 67cc chamber I'm staring down the barrel of 11:1. Our fuel is equivalent to your 91 octane and I was planning on going with a big hydraulic roller anyway, but how big to bleed off the excess squeeze?:oops: