How Big can a 5.2 get?

Engine is slowly getting somewhere, next thing to do is to measure piston to head clearance, pistons are sticking .018" up from the hole so with Fel-Pro 8553 gaskets I should get Quench around .035".
Well, this didnt go as planned... Somehow Ive got piston to head clearance everything between .038 and .047 .038 is good but .047 is not... Dont know wtf should I do, block is decked allready and crank balanced.