Engine:
2005 5.3 LH6 Block
799 heads milled .010" with light hand touchup work
Summit Racing Stage 3 LS Cam (231/242 113+3, .600/.600 Lift)
.048 Head Gasket
Long Tube headers

Is it worth getting a Dorman LS2 intake over a stock LS2 intake? I haven't been able to find a good back to back comparison, especially for a smaller 5.3L.

 

Dorman

 

Is there any dyno graphs? How much am I leaving on the table with a stock LS2 intake?

 

I doubt you will see back to back dyno graphs. The intake is too new, and most people that ditch the LS2 intake are not stepping up to a Dorman, they are stepping up to a fast. Since you have neither, the Dorman is the way to go. The stock LS2 has worse characteristics than the LS6 intake which outperforms it even on a smaller throttle body.

There is a massive flow data thread in the Gen 3 section (you're actually asking a gen 3 engine question) that goes through which intakes flow the best by restricting the heads the least. https://ls1tech.com/forums/generatio...sxrt-more.html

The Dorman LS2 intake incorporated some of the FAST design work and outperformed the LS6 intake, almost as good as the TBSS intake. Jump to post 674 for the list from worst to best.

 

Just get a FAST for the LS2 Cathedral port, you'll be happier and $ ahead I went from a stock LS2 manifold to a Peak speed shop Radically ported LS2 Manifold ,and lost HP a lot, to a FAST and gained it back +, the thing that I'm most happy about is fast had already went thru 3-4 model changes 90mm, 92mm, and 2 102 versions before making the cathedral port version and I didn't have to butcher my firewall on my corvette like you had to do with the early versions

 

hello

 

LS2 vs Dorman LS2

Dorman LS2 much better.

The LS6 intake out flows and makes more horsepower NA than the LS2 intake. The Dorman LS2 intake flows more than a stock LS6.

In a NA application the Dorman LS2 should out perform the stock LS2. I seem to recall reading Dorman even up some effort into making sure the Dorman LS2 was better than the stock LS2.