I was wondering if the Keith Eckert aluminum headers would actually do anything for a 1998 7.4 MPI. I need to replace the manifolds and risers anyway so I wouldn't mind spending a little extra if it would give me a horsepower increase of about 20 to 30. This system received praise in Dennis Moore's book. Any suggestions?

The boat is a 22' Scarab 7.4 MPI Bravo, new 25" Mirage Plus. Right now it is getting about 61-MPH on the speedo at 4800 RPM (However it seems faster than 61)

Thanks
Roby

You might pick up a couple hundred RPM and MAYBE 1mph IF ANY! The Keith Eickert headers are a very good design though. You'd have to do other upgrades to the engine in order to see the real bennefit of an aftermarket exhaust system when it comes to the 502MPI. Other than that an aftermarket exhaust like the KE headers will dress up the engines much nicer, are light than the stock Merc junk exhaust and will have a much nicer sound and tone.

I second Kaama. Absolutly and excellent design...just a little overkill for your current application.

I do need to replace the stock ones anyway so are there any that would be better than stock and at least have a better sound and or appearance?

Thanks for the reply's
Roby

I was talking to Keith a couple of weeks ago and he had nothing but praise for these headers, however they were too expensive to produce and all the tooling was sold to a company in California. Sorry, I do not remember who it was.

Roby,

If the KE's are no longer available then an aftermarket exhaust system something like a Stainless Marine or GIL look very nice with a one piece smooth elbow type riser/tailpipes. I would avoid any type of system that has risers with lots of 90* bends/turns. The Stainless Marine exhaust system are available with a the riser and tailpipe together as a one piece dry unit----all polished stainless steel, the manifolds have a black glossy finish on them. These will make your engines look and sound VERY NICE! Have FUN!

My $0.02
I think all the 300-330hp motors still run very small intake ports on the heads. That seems to be the restriction in increasing hp on these motors. You would probably have to do headwork, or change heads, and change your cam for the headers to have any effect.
Save your money and just replace the originals. BTW, you can probably find nearly new used Merc exhausts cheap.
Gary

Dennis tells you what to look for in a exhaust manifold.

I believe Innovation still had some sets they were selling. If you want the name of the co with the tooling let me know.

Innovation has several sets, they're selling them for $2000 per pair.