Difference between a 4.8 and 5.3 ls engine

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So I was browsing Craigslist last year and found an advertisement for a 5.3 4l60e combo. It had been pulled out of a 2006 roll-over and the truck was gone. I had no VIN or any documentation to tell what it was. I bought it though because the engine cranked over great and the compression was good. Well as time went on I cleaned the engine up and noticed something sticking out from the head gasket. A little flange with 4.8 stamped into it. My heart sank. Well sure enough I pulled the oil pan and checked the casting on the crankshaft. I had a 4.8 on my hands. I'm happy with the 4.8, I just want to list a few of my observations to maybe help others identify what engine they have. And hopefully others can chime in with observations as well for other eras of LS engines.

Of course if you just aren't sure about the engine, pull the oil pan and internal baffling and check the crank. It's not that hard and you can easily see the crank casting number.


So first is the picture of a tab coming off of the head gasket. This tab was on both sides of my engine. Stamped on the tab is 4.8.



Here is a closer shot of the tab.



Something I noticed later and I can't verify now (b/c I painted over the block) is a green paint mark over the 4.8 block casting. This picture is from the front of the engine.



Although when I was looking back in my photos and looked at a picture of the backside it almost looks like the 5.3 is highlighted. So I don't know how reliable the green paint is. Maybe others can verify.