440 build working with what I’ve got

Whatever the pistons weight is a balance job will be in order and if you’re going to balance I would polish the beams on the rods and install new bolts if they are stock.
I’ve never broken a stock polished rod and I have turned them to 7200 with both a 3.75” and 4.15” stroke.
Fortunately, I have the full rotating assembly that previously had balance work done, evident by the Mallory metal in the crank, that the domed pistons came from, the forged crank and 6 pack rods were all together in a block, one piston was destroyed in removing them from the block. I got a newer style replacement for it, but it is lighter, I am currently trying to locate a heavier wrist pin to balance it out with the other pistons. That way I can avoid a trip to the machine shop, hopefully. As far as boring the block from .030 up to .060, my buddy does some machine work and has a boring bar.