i found a set of je pistons and crower rods (used). how do you tell if a piston is high comp. or low comp? also how can you tell the compression ratio of the pistons? i looked inside the one of them i saw 87 engraved inside the piston. what does that mean?

 

It is either a dome shape or dished shape. The dome shaped pistons are higher compression, while the dished style are lower compression. The 87 that you see stamped into the bottom of the piston is not the bore of the piston. I have a set of 84mm brand new, they have 83 stamped on the bottom of them. You need to take measurements of the piston, call JE and ask a tech rep he can tell you what compression the piston is in relation to your block and head type.