I am looking at purchasing a car that has a newer GM crate motor in it which the seller is saying is a LS376/525 which I have a sneaky suspicion that the motor is only a base model GM Crate LS3 motor. How do you tell if a gm crate motor that is installed in a car is an LS3 or an LS376/525. Is there a part number on the engine that i can compare to the GM website part #'s, please help. I found these numbers layered on the block W529585 if that helps

Thanks

 

It's just an LS3 with a cam swap, right? He may have spent $6,000 or whatever it costs but really it's a $300 cam swap.

 

The only thing that I'm aware of is the tag on the block behind the driver's side cylinder head. The ls376 is an LS3 with the sucky GM ASA cam, complete with its terrible idle quality. The valve springs, rockers and everything else are identical to a stock LS3