NiftySix

So I just bought what I was told was an LM7 from a '06 Tahoe. I decided to verify that I really got a 5.3 and not a 4.8. (This seems like a recurring theme on many threads.) I don't have the VIN and from what I've read there is really no way to tell the difference from the exterior. I don't see a paint marking on the 4.8/5.3 casting on the block. I found some threads that mentioned the head gasket tabs. Mine said 4.8, so I was not happy. I stuck a scope down the spark plug hole and it looks like it has dished pistons. Here are a couple of pics of the pistons and one of the "4.8" tab. They are not the best quality, but it looks like they are dished. Could this actually be a 5.3???

mark21742

If I am correct the 5.3 had fished pistons, the 4.8 had flat tops, so if I'm right, then you got a 5.3

bww3588

iTrader: (49)

4.8 and 5.3 used the same head gaskets. and yes, only the 5.3 had dished pistons, looks like you have a 5.3 on your hands.

supersick99z

iTrader: (66)

Pics are a bitch to see, but pistons looked dished=5.3!

NiftySix

Thanks for the advice. That is what I thought, but the 4.8 on the tabs had me discouraged. And yea, the pics are hard to see. It was the best I could get with the scope. Thanks again!