my friend wants to shave his pistons? i have never heard of this being done before and dont think its a good idea. can this be done and if so what are the advantages/disadvantages of doing?

 

for what purpose?? i've seen it done on ls/vtecs (although just the relief pockets) before for valve clearance. although i would let a machine shop do it for balancing purposes. i've also heard of shaving pistons in v8's for clearance due too block mods.... but i don't think there would be any performance advantages