I'm thinking about upgrading my Stainless Marine Manifolds to headers. I thinking about CMI elbow tops. Would I gain much in with this swap? Someone posted a comparison of differnent manifolds a while back which I tried to post but it wouldn't let me post an excel file. It looks like I would gain a fair amount of torque and a little hp. I'm spinning my engine around 6000 so I think the header would also help a bit more on the top end. What are your opinions on this.

How much HP are you making? Headers might not do much for you say if you make 500HP or so. but if you have a 750-850Hp motor, the headers would probably do more for you.

I'm making around 550 hp.

I wouldn't personally bother with headers at 550HP
A really good manifold would be fine.

I got a friend with a boostpower 550 in a cole superhawk it has a really good set of Manifolds, and the think flat out honks.

The stainless marine product seems really good, and a lot of credible East Coast guys rave about them.


Uncle Dave

At 550 hp, I really don't think you will see anything on the speedo. Yes, it may help you gain a few hp (maybe even 5 or 10), but I don't think you will really notice the difference in mph gained.

I wouldn't do it just to do it. However, if something is wrong with the manifolds and they need to be replaced, then I would go with the headers instead.
Eddie

Good high quality manifolds work great, and any kind of real exhaust system is the foundation upon which all engine work lies.

The stuff your boat came stock with was likely junk.

Here is the cole- I spoke of.

With a single 24P SS 4 blade - this thing blasts a boat full of people with anything in tow on plane like a competition ski boat, and winds up to around 72 with a basic big block running a high quality manifold.



Uncle Dave

I'm happy with the stainless marine stuff I have now. I'm trying to think of ways to get another2-300 rpms ot the engine but I'm drawing blanks. I think I've done about everything that I can. The only other thing I'm thinking is to swap the Steath intake for a really good single plane but when I was building the engine Dave @ Wesco said I was splitting hairs.

U.D. that boat looks pretty fast, just wouldn't want to lauch a wake at that speed.

You guys forgot one thing........how cool headers sound compared to manifolds!!!! For me the sound alone is worth it

I totally concur with Eddie @ Young and Uncle Dave, save the cost and spend it getting that engine to make that 550HP at 5000-5500 rpms where the increased torque and usable power will do more good for your boat. 6000rpms on your engine seems a bit on the high side for durability and longevity?

Best Regards,
Ray @ Raylar

Friend with a 600ci n/a 25' Talon went to Hardin Marine Shortie Tube headers from Imco Manifolds and and saw no difference. Looked better though!
It depends on what rpm your engine was built to run at,weight of boat,etc.
I ran full tube headers on a 20' Sutphen and picked up close to 400 rpm, turned 6400 rpm.