They are double ringed pistons. If you rebuild get the 03 pistons. I think they updated those so you can't even get the original 02 pistons anymore. If you run it on 87 you are seriously asking for troubles. 91 at the least. Put some 300 mains in and rock on.

Any more questions just holler. I've completey torn this thing apart so I could tell you what bolt goes where.