Ok here's the rundown, I just bought a used LS6 shortblock plus top end extras for $1400 about a month ago.

Upon removal of the included heads prior to installing my TSP LS6 Stg 1s, the shop noticed there were two different sets of pistons. On one bank there were what they assumed the factory stamped pistons, and on the other side there were pistons that weren't stamped. Now he did say there was an even amount of carbon buildup on both sides, so he guesses it was ran that way. Is this something to be concerned with. Seems like a lot of money to spend to have things go wrong due to this.

Does anybody have any idea why there'd be different sets? Did GM install these unstamped pistons when they were doing the piston slap recalls and rebuilds? This is out of an '01 Z06 w/ 18k miles if that matters. I know new pistons could be pressed in, but I can't afford that as of right now.

 

what kind of stamp marks? they all should have the teflon coated skirts on all of them I'd say roll with unless they see a problem

 

Well the carbon was even on every piston and they all had about the same carbon footprint. We bolted the heads and the intake on and did a preliminary leakdown test. Every cylinder was w/in 2psi of one another so I'm running it. All else fails, I have my factory LS1 on the side I can just rebuild if something goes wrong with this one.

 

Note: this is not my block, just using this pic for representation. If you look at the two pistons next to the messed up one, you'll notice a stamp on them. This is the stamp I'm referring to.



Like I said, 4 of mine have this marking and the other 4 don't.