The pistons will work fine. However, before compression can be computed we have to know the amount of deck clearence (the space between the top of the piston and the top of the bore) plus the head gasket thickness as well as the bore diameter of the gasket.
If the block hasn`t been decked there`s no telling what the deck clearence is from end to end being 99% of sbc`s are tipped. To do a mock up assembly of this I install the number 1 and 2 pistons as well as the 7 and 8 pistons and check the clearences between them. The 1 and 2 maybe .025 and the 7 and 8 might be .030 you never know until you check.