I.D. 340 parts

Thanks for the info.10-1 compression sounds pretty healthy so hopefully I can keep those pistons and just re-ring them.None of them were labeled which cylinder they came from so I probably don't want to use the old rings again.

Greg...you don't want to reuse the rings regardless. Get the bores mic'd and checked for roundness. If they check out, then you'll want to go ahead and have the holes honed, or at least scuffed to allow the new rings to seat. You can get .040 "File-fit" rings that are slightly bigger than stock .040 rings that may allow you to use your current pistons.

None of them were labeled which cylinder they came from

Check the big end of the rods for cylinder numbers.

Just a start.....