azz seat dynos are a great thing.

I'm sure there is. Not trying to argue about it........wasn't the intent of this thread. With that said it seems as though when Keith first developed this exhaust (1 7/8 tubes and 4" tails!) there weren't the large displacement engines and huge flowing cylinder heads producing the numbers that are becoming commonplace today.

Before Eickert had them there was PF marine who designed them. Those headers worked great on their PSI blown motors that run their Black Thunder close to 140mph. May want to get Coolermans input on them as I believe his father was the P in PF marine.


http://youtu.be/00ZI75CWml4

I think what he really meant is he has one of those Dyno's that he uses regularly.

What is the ID of the stock 525 CMI headers?

My guess is 1 7/8. But getting back to the higher horse stuff. We used to run 2 1/8 back in the 70's on a big block drag race motor with not even close to the power levels of these marine engines. So, I can't see anything smaller than that making any sense!

1 7/8 square port? If so does that help flow. That's what my stainless marine manifolds have.

The fact that they are an consistent 1 7/8 oval runner 32 inches to the collector and they'll likely never leak is what makes the thunder & lightning headers so awesome. They sound like nothing else out there, very distinct exhaust note for sure. Besides the Gen III's, the Thunder & Lightnings are in a completely different category vs Stainless Marine.

I really like SM, but you are at that point comparing a manifold type to a true header regardless of runner size or shape. And for the folks that don't like the look of the thunder & lightning headers,,, seriously? Do you look at your engine that much? To each their own, I think they look pretty cool and they are proven to be one of the best you can buy.

[QUOTE=chrisf695;4325768]So why are these used on other 1000hp supercharged racing engines with great results?[/QUOTE

I used these headers on my twin turbo setup making 1200 HP for 4 seasons in the late 90's. They worked extremely well. Eventually I switched to a set of Dana marine cast aluminium and ran them at well over 1500 HP.

hell,ls engines are running 1 7/8" headers.and they are small