I'm new to the LS swap world and I've been researching and reading just about anything I can. Every now and again I come across a video or website post that says this stock part from a gen IV is better than that stock part from a gen III. For example, supposedly the gen IV piston rods are better than the gen III rods.

My question is, what stock gen IV parts can directly swap into a stock gen III and is considered an upgrade/better?

I'm rebuilding an LM7 to swap into my 93 jeep YJ. I have everything completely disassembled and I just got the block back from the machine shop. I plan on keeping it as stock as possible, but if I can do little upgrades here and there, I figure this is the best time. Thanks.

 

If it’s stock and you’re keeping it that way, it’s probably not worth it to swap to Gen IV parts. The main advantage is that the Gen IV rods are stronger, but the Gen III rods are more than capable for over 500whp.

 

The differences you speak of are of little to no benefit in your situation. The LM7 is a very rugged engine, and will serve you very well in stock configuration.
You might, however swap in the LQ9 (still Gen III) cam (196/201, .467/.479,116LSA) which will give a nice little boost all over the curve. Or the Summit Torkinator which has very similar specs (200/205, .550/.550, 113+4LSA) plus more lift for likely less money. Put LS6 spec springs in the heads too. This will make it a solid runner that will totally appear and sound stock.

 

That's good info about the Gen III rods. I have no interest going anywhere near 500whp, lol.

 

Interesting. Something else to research. If going that route, will the stock push rods and rockers still work?

 

Yes on both counts. Check yours for straightness by rolling on a pane of glass.