Anyone know what the Primary I.D. of the runners are in the Thunder N Lightning / Eickert Manifolds is? Asking for a friend :)

So with the risk of used headers, how much power is there to be gained in headers vs your sm;s? and what does that power increase equal in increased mph? now is that increase worth the possibility of a leak and the possibility of a gernaded engine? Yes, your buddy can hot glue stainless,but you have to be lucky enough to find a leak first before it does damage.

Headers can most definitly ,make more power which can make more speed but only you can decide if the risk is acceptable. As far as the holes in the transom lining up... its not that difficult to plug and recut if they dont. You have a white solid color boat, not some mega dollar spectral vomit paint job to match so its really not that hard.

I'd probably adjust the tailpipes, not the fiberglass. IF it were slightly off, and the existing holes just need slight adjustment, you can open them up, and use a larger trim ring on the outside of the transom if need be. Last thing you wanna do anyway, is have a super tight fit on your tailpipes going thru the transom, esp if you boat in big water. Chit moves around, and you don't want the tails acting like prybars on the headers, putting a bunch of stress on them.

If you dig the designer of the KE posted about them... To save to a lot of time looking, they are 2" i.d.. If I can find the post I'll post a link.

Mild Thunder
http://www.offshoreonly.com/forums/g...-question.html

Here's a thread from awhile back , looks like 1 7/8 oval

Cool, thanks

He's saying 1 7/8. Same as my Stellings and standard CMI headers. Still on the small side.

Wish we had a manifold setup just like that avail, with 2 1/8 primaries and 4.5" collectors!

Here is the link to the answer. At the time he was running 1200 hp through them, last I read he was up to 2000 hp through them. If you start at the beginning of the post there is a lot of good info.
http://www.offshoreonly.com/forums/g...headers-3.html

I know diamond claims 1 7/8" but the guy that actually designed them claims 2". I'm going with the guy that designed them. There are guys running some huge power thought them, I think they are more than enough for what any of us will ever build.

I was talking to one of Eickerts old partners when Keith still had the rights to his name, prior to selling to Hardin. He told me at that time there was no production header that would out perform the K/E including CMI big tubes. The big tubes may have a bigger id, but the runners are not even close to the same length, so maybe the bigger id is countered by different length runners? Who knows?

The cool thing about CMI, is they will do custom setups. In their "big tube" series, you can choose from 2 1/8", 2 1/4, and 2 3/8 primary id. You can choose to step the header as well if you like. Im pretty sure, their Sport tube, and big tube, have similar runner lengths as the KE style manifold. The elbow tops, are much shorter. I think thats why don't dont recommend Elbow Tops on N/A engines.

Stellings used to make some big tube headers, wanna say they were 2.25ID if I recall. My old "green" stellings, are 1 7/8. I believe the "green" headers I have, were originally spec'd for Mercury's 575HP 540 engine back in the late 80's.

The cool thing about big blower engines, is you can just keep pounding more and more boost at the engine, and even though the exhaust might be restricting it, its still making more power. Now , when you take that exhaust off, and slap on something else, you might see the boost drop, and power go up. So while I can appreciate someone running big numbers thru a particular exhaust, I'd rather see it tested against something else, to see if in fact, theres something better.

For guys like us though, I think its hard to beat the KE style manifolds, or , if blown, the GEN III 's. For the big money guys, some Inconel big tube CMI's, might be a better option. I seen those inconel headers on a 45 Cig at loto. I didnt even know they did that!