LS1 Piston rings
I'm saying you can't take a l33 to 0.120" over, up to ls1 size and then another 0.030" on top so a total of 0.150" over. All the aluminum 5.3 blocks will go way over like you said I just mean this is a ls1 block from what the OP said and I'm saying they make pistons for that, even though they shouldn't for the most part.
I don't have the casting number wrote down anywhere easy for me to send, BUT I have looked it up it shows as an LS1 and the guy I bought it off of said it was out of a 2002 Firebird.
I have fit the pistons into the block on to a crank without rings and they tap in just fine, personally I don't know what to thin piston walls would look like but they look fine on my end.
I have fit the pistons into the block on to a crank without rings and they tap in just fine, personally I don't know what to thin piston walls would look like but they look fine on my end.
You could never tell, the top of the sleeve is thicker than the actual sleeve it has a "hat". The early blocks from 97'-98' were listed as 0.005" from GM and the later 99'-04' blocks up to 0.010" from GM. I could see going 0.010-0.015" on the early block and it might live, but not 0.030" Have it sonic tested if it will even pick up at least the sleeve..
Thread Starter
Teching In
Joined: Sep 2025
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From: North East Oklahoma
how did you look it up if you dont have the casting numbers? You may want to listen to these guys before you spend money putting an engine together and tearing something up. Trust me I've been down a long road with my truck and every single part I put on my truck that I was told not to use i ended up taking back off and replacing. Ive spend double the money building my truck because of it.
Thread Starter
Teching In
Joined: Sep 2025
Posts: 6
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From: North East Oklahoma
TECH Fanatic
Joined: Oct 2022
Posts: 1,708
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From: Louisiana
Could it be that this particular LS1 block was re-sleeved? I know that back in the day they used to re-sleeve and build 427's from an LS1 block.
At this point I'd run it with a chance that you're running this on borrowed time..
At this point I'd run it with a chance that you're running this on borrowed time..
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
I mean….just because the ring package is 1.5x1.5x3mm for a 3.898” bore doesn’t label it LS1. I just bought a ring package in that exact dimension for an overbored 5.3 iron block build. I could have gone another .030 and found rings easily…but it doesn’t label my build here an LS1. Total Seal, Hastings, and just about any other known reputable ring manufacturer will build…or even prolly has in stock…any ring in just about any dimension you want.
