al,
i am not against reusing the old block, but am against the 80 overbore.
had good luck once with my F450 diesel. one piston lost 1/2 of a skirt. the piston wobbled bad enough to allow tapping against the head. took the block in for a check and found all bores were in perfect round with no wear. bought new standard pistons and ran again. still pulls like a champ.
sleeving the bad cylinder is a option. i will bet the other cylinders will need the bore though. i am also not against putting a different size piston than the other bores. as in, you sleeve the one bad one and put in a standard piston. i am against boring the 1 to 80 over though.
there is probably a reason the piston gave up. did the engine ever ping under load?