babooze, i work at a machine shop. we would waste hundreds of dollars a month if we just randomly ordered pistons without knowing what overbore we are going to need on the block. the final size is dependent on the damage caused to the cylinder. the machine shop will tell him how far they need to take it. if its beyond the largest overbore, then theres no saving it, unless they can knurl the piston (which i HIGHLY doubt). the overbore sizes for these motors are relatively close together, so he wouldnt have much problem at all having them clean it up and give him a measurement. he could then tell them what piston sizes he has available and they could finish it so it would work for the piston.