CMI headers vs. Stainless Marine Gen III
 

Fellas,
I read the pro's and con's of headers vs. manifolds, each has it's benefits and drawbacks.

I'm in process of installing a 509ci BBC with radical roller cam and 10:1 compression. With that said, I could use the cylinder scavenging benefits of a full 32" runner. Stainless Marine makes a (in my opinion) a bullet proof Gen. III manifold, riser and stainless tail pipe, however the 15" runner scares me. Is it worth spending a little extra $$ for CMI's 32" runner header? (and yes, I know the headers look kick a$$ and probably sound a little better)

My friend has the GEN III's on his Falcon, and they have worked flawlessly.

Oh yeah, the boat is a 1971 Donzi GT (looks like a Classic, but is beamier) and will utilize Arneson's extension box and #6 drive in salt water.

If you have the $$$$$ go with the CMI. Just got them on my boat. They do look KICK ASS !!!!!!!!

Looks aside, The KE Manifold/header is by far the best HEADER, (Full 32" runners) and is manifold TOUGH, (No leaks!) on the market. I have run my set on my HP500 for 4+ years in the Atlantic ocean and have no problems. Plus, I don't have the H2O reversion problem either with my KE's! The only down side is they are not the eye-candy that some people perfer, and they are alittle loud! I put Shotgun III's mufflers on them also, again, with no problems.
Hope this helps,
MD

I can't vouch for Stainless Marine, but I will say that CMI has been nothing but helpful in setting up my exhaust. Got the wrong tailpipes (my fault), no problem, had custom ones made in a week and 1/2 - a perfect fit. I couldn't measure from the outside of the boat for custom tailpipes (Formula with Silent thunder platform), so they helped me figure out dimensions from the inside. Tore a header gasket adjusting rockers, no problem, overnighted me a new pair. They've been great.

Just my experiance.

Scott

Tried both types on my naturally aspirated full roller, 10:1 compression, 588inch tall deck. The Gen III pulled 5 more HP above 5,000. The CMI's are prettier, but the Gen III's work, besides, Iam starting my 4th boating season, and they still look brand new.

Nate...

Do the rest of your Donzi brothers know what you are up to?? Good thing I'm putting a 'Hawk on mine. I'll need to just to keep up!!

Woodsy:D :D

CMI all the way. I bought a set with the "cool collars" and they perform flawlessly. Also I found out a trick that makes them last years longer in salt water apps. On the runner, remove the rear cap and replace them with an adapter and a 1/4 inch hose. Run the hose out of the hull just above the water line thus allowing them to drain automatically after each use. I also think the CMI's have a lifetime time warrenty. Otto

Pat at Active Thunder is putting CMI on my KE675's, I have them also on my Sonic, never have had a problem, 88 hours and no leaks.:D

Troutly, You can see your reflection in them, eye candy it is.:D

Troutly,
I'm just an "Enginerd" by trade/schooling, therefore I make most of buying decisions based on performance/reliability data, (Enginerd's curse!), just like @ work! It's funny, when I look @ KE's headers, I see a BEAUTIFUL example of ENGINEERING/DESIGN and reliability, but, hey thats' the curse I mentioned earlier.:D
I would like my next set(s)? of KE headers to be coated the Mercury Racing Blue, if he can do that? I wonder if KE will polish them, that would improve the "Eye Candy factor"? Hmmmm?
MD:D

600 hp and above stainless marine are the dominating exhausts- have used them on numerous vessels. I would recommended them for your application, in fact I have a set with just a few races on them, you may have to have the tail pipes altered depending on transom height. Can save you 30%, wish I would have known you were building one, have a 12:1 510 C.I.D. runs on 104 turn key extra msd parts included, old supervee light motor with couple races on them. I can make someone a hell of a deal or will separate exhausts- call me (813) 249-3049 and ask for me- AL.

Hey Scot just wondering I have a 311 SR-1 with TRS Drive 87 Model, I just bought new power and want to change the Exhaust System want to know if you purchased the system directly from cmi and what size is your boat, Thanks for your anticipated help

Ditto:cool:

Since you guys are talking about us I thought I'd chime in.

The KE Header was designed for one thing and one thing only, to MAKE HORSEPOWER! Ever since this header was designed back in the early 90's, we have made the claim that it builds more power than any other system on the market. That claim still stands today.

If you want to open your engine hatch and impress someone with your shiny bling, then this is probably not the exhaust system you're looking for.

BUT, if you want to run head to head with the same boat, equipped with the same power as you, and the only real difference is the exhaust, then the KE Header will make you the winner every time!

Check the comparison in the graph below, the KE Header will always be the one to make the most horsepower and the most torque. That translates to SPEED.

Then when you compare prices you'll also find that it is not as expensive as many of the tubular stainless headers on the market.

You're choice. Performance or Bling, what do you want?

You can check out the details at http://www.keitheickert.com/products...ke-exhaust.htm

I know this is an old response, salt water is not the death of these headers, its the heating and cooling cycles. You can only make stainless red hot then cool it so many times before it becomes brittle. If you like to take a lot of short blasts then the go with the manifold instead of the header.

We spend how much on our engines? I say for the few bucks extra go for bling and the power. CMI.

The heat cycles are definitely a factor but vibration is a key factor too..

For the money we spend on these systems they should last longer than 4-5 years before possibly needing a repairs.... i know guys, who use there boats a lot, who got a leak in the first season. Then rare cases, like yourself, where they last a while. But after 6-7 years they're just about ready for the junk pile..... Plus, If I spend $7K on an enhaust sytem I want it to last and if I pay the $7k, I want some assurance I won't get a leak and drop a valve.

I'm sure the Stainless Marines in my old Scarab are still in tact and have many more years on them. Stainless Marine come with a 5 yr warranty.

Can CMI or Stellings step up to the plate and match the warranty? :eureka:

How come the K/E's are not compared to the stainless marine 3's? Smitty

my stainless marine drys are 13yrs old now:p :D

Yes, some comparison numbers between those two would be interesting to take a look at.

I`ve had them both and after the dyno numbers climbed by the 30 horsepower. I stayed with the Gen III`s.....Yes the CMI`s look cool however, they don`t make more power than the Gen III`s. We had Stellings in our Cigarrete race boat and now we have the Gen III`s.