GM Gen 3 vs Gen 4 LS Engines...What are the Differences?

LS engines are hot because of their availability, affordability, and compact size. That makes them ideal for engine swaps into seemingly anything (sorry Ford guys)!

But which LS engine are you looking at--Gen 3 or Gen 4?

If you're scouring a junkyard for a potential LS swap, there are some telltale signs to discern between a Gen. III and Gen. IV LS engine. Things like front timing cover, knock sensor location, cylinder head style (cathedral ports), AFM, and other components are key clues to which engine family you're looking at. In this video we cover some of the main visual differences between the two engines. Once you've determined if you've found an LS Gen 3 or LS Gen 4 engine, you can narrow the engine down by RPO code.

Watch this video to delineate between engine families, and then check out this link to continue your LS engine identification: https://help.summitracing.com/app/ans...