If the block has already been bored and it needs a rebore, I'm going to get a different block as I don't want a 0.060 over engine I believe in only boring enough to clean up the bore,if a 0.020 over will do it then that's what I'll do
For the power level you want I would use a .060 overbore if I had to. The difference between a .020 overbore and a .060 overbore is .040 and you take half of that per side. That’s .020. If .020 is going to kill the block it wasn’t worth building the block at any overbore.