LS1Tech Resisdent Experts
 

Ok, new to the forum. I've enjoyed lurking around and gathering information. Building a second generation Camaro. Decided to go the 5.3 route and bought one from a guy on Craig's list. He had a mechanic pull the motor from his wrecked truck. The mechanic wanted the motor, but couldn't come up with the cash. My question is this: How can you tell it's a 5.3 and not a 4.8 without the VIN from the original vehicle or tearing it down and checking the stroke? Just wanted to make sure there wasn't an ol' switcharoo! The Blocks are the same bore and casting as it's imbossed on the front "4.8/5.3L". Do any of the other casting numbers give this away or are there any other tell-tell signs that this is, for sure, a 5.3? Got the 80K '02 motor and all the accessories, computer, wiring harness, 4L60E transmission, and even the fuse block for $875 so I don't think I did too bad. Hoping I don't have to buy a new rotating assembly anytime soon. Thanks in advance.

Those motors had a headgasket tab with 4.8 or 5.3 sticking out. Pull a plug and feel the top of the piston with a screwdriver. The 5.3 had dome pistons and the 4.8 had dish. The only way to be absolutely sure though is to pull the pan and ID the crank.

O.K. I couldn't find anything when looking for 4.8vs5.3 engine identification because they use the same blocks for both. However, when I thought I had a 4.8, because the tab for the head gasket was stamped "4.8", I started searching for 3.622'' cranks I run across a couple of sites that offered useful info on identifying these motors. I believe this information will be useful to anyone going the 5.3 route like I did, especially if you don't pull it from it's original vehicle which removes your ability to rely on the VIN. Internet shoppers, ARM YOURSELF!

The 5.3, infact, has the Dished pistons! The 4.8 has Flattop Pistons. The piston is clearly visible through the spark plug hole. This is a sure fire way to tell it's a 5.3. I almost couldn't believe my engine was assembled with head gaskets stamped 4.8, even though they are the same bore as the 5.3, and had Dished top pistons. So I flipped the motor on the stand and removed the oil pan, windage tray and oil pump pick up arm and low and belhold, there it was, the crank with the 12552216 casting number. It's a 3.622'' stroke crank. The 4.8 crank casting numbers are 12553482 '99-'00 with autos(and all trucks from '01 and up) and 12553312 in '99-'00 trucks with manuals, at 3.268'' stroke.
I hope this info is useful to someone. The 4.8 and the 5.3 usually run the same price at the salvage yards, so the extra stroke won't cost you a thing if you know what to look for!
The following are just two of the sites I found most informative:
http://www.enginebuildermag.com/Arti...all_Block.aspx
and
http://www.pera.org/articles/eb120317.htm
FYI: The 4.8 also has a longer Connecting Rod at 6.275''. All other LS motors use a 6.096'' Rod according to the mentioned sites.