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Old 05-17-2011, 07:06 PM
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Question Aftermarket exhaust manifolds or headers

I would like some opinions on the various aftermarket exhaust systems and headers. My Boat is a 29 Twin engine Fountain. The motors are 502 MAG MPIs with B&M Superchargers putting out about 600 Hp each. I also have the CPTs Call/Silent choice with the diverters and Solenoids to engage the system (I just flip the switch). I have about 350 hours on the motors right now and I am looking at getting rid of the stock exhaust manifolds. I do not want to spend more then 3.5K per motor so the high end systems are not what I want. My goals are to: 1- Have a lighter weight exhaust system; 2-get a durable long lasting system; 3-get some increased HP gains, let the engine breath better.
I am currently looking at the Stainless Marine and Lightning systems that would adapt to the CPTs Call/Silent choice.
What would you recommend?
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Old 05-18-2011, 11:51 AM
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I'm currently running the SM std on my 540's, run in salt constantly, flush after each weekend but not each day, since 2006. had shop tell me one manifold leaked at test pressure on outside fitting, but when I got boat from shop, I couldn't make it leak at all. If it leaks, it will be into the bilge, NOT into the engine, so I am waiting to see if it ever does. Got replacements waiting just in case. I think the shop wanted to sell me manifolds at THEIR pricing, not that there ever was a leak. Also, they save about 40 lbs per engine over cast iron. Their power is just a little off full tube headers, but then the price and durability is off the charts in comparison. I'd rather build an extra 50 HP into the engine and use a durable manifold system than try to "extract" an extra 50 HP by using a less durable system. Started using SM in 1996 on a small block lake boat.
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Old 05-18-2011, 12:01 PM
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I second the stainless marines. Also check out Keith Eickerts, I don't know if they will work with switchable exhaust but if you give them a call they will tell you! I think they're around $3000 a set and are true full length headers but are aluminum not stainless. Very, very durable!
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Old 05-18-2011, 04:28 PM
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Originally Posted by rgrgoog
I would like some opinions on the various aftermarket exhaust systems and headers. My Boat is a 29 Twin engine Fountain. The motors are 502 MAG MPIs with B&M Superchargers putting out about 600 Hp each. I also have the CPTs Call/Silent choice with the diverters and Solenoids to engage the system (I just flip the switch). I have about 350 hours on the motors right now and I am looking at getting rid of the stock exhaust manifolds. I do not want to spend more then 3.5K per motor so the high end systems are not what I want. My goals are to: 1- Have a lighter weight exhaust system; 2-get a durable long lasting system; 3-get some increased HP gains, let the engine breath better.
I am currently looking at the Stainless Marine and Lightning systems that would adapt to the CPTs Call/Silent choice.
What would you recommend?
You will never beat the overall performance of a tube style header but the manifolds will offer you a durability option that's better than headers. You really need to determine if longevity or maximum performance is the concern. I doubt at 600hp that there is much more than 25HP difference between the GiIL/Hardin system and a header. Stainless marines systems are also very good. The first thing you should check is engine center lines as most of the 29's with twins are so tight in the center. You want to make sure whatever you look at will fit.

http://www.keitheickert.com/p-13399-...ock-bravo.aspx

http://www.keitheickert.com/p-12816-...ed-risers.aspx

http://www.keitheickert.com/p-14437-...atibility.aspx
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Old 07-20-2011, 08:55 AM
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Originally Posted by KEPP
You will never beat the overall performance of a tube style header but the manifolds will offer you a durability option that's better than headers. You really need to determine if longevity or maximum performance is the concern. I doubt at 600hp that there is much more than 25HP difference between the GiIL/Hardin system and a header. Stainless marines systems are also very good. The first thing you should check is engine center lines as most of the 29's with twins are so tight in the center. You want to make sure whatever you look at will fit.

http://www.keitheickert.com/p-13399-...ock-bravo.aspx

http://www.keitheickert.com/p-12816-...ed-risers.aspx

http://www.keitheickert.com/p-14437-...atibility.aspx

Yes and mine are tight. How do I go about (what is the procedure) for measuring the centerlines and getting an accurate number?
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Old 07-24-2011, 04:57 PM
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Hi rgrgoog,

I would consider checking into the Dana Flow Torque exhaust. I have them on my 454 MAG MPI and love them. Here are some pictures of them.









My first time out with the new exhaust I notice a much stronger acceleration all through the RPM range and it sounded awesome, very throaty and loader. Do to the water conditions at the time, (lots of chop and very windy) I couldn’t really put them to the test and run it hard, although, I would suspect from the improved acceleration the RPM range could possibly increase slightly as well. Who knows, maybe I’ll even gain a MPH or two on the top.

As for the weight, most definitely, these new manifolds are much lighter. Those stock cast iron manifolds weigh a ton! You will see what I mean when you take yours off.
Considering your setup, I would think you would benefit a great deal from them.

As far as clearance issues go, my concern was vertical, anything much taller than stock wouldn’t clear the engine hatch cover. The Dana’s do fit very nicely, they are not big and bulky like some I’ve seen. They fit as they should, nice and tight. As you can see from my 3rd picture, they are very compact the way they hug close to the engine. This could be a very important factor with close quarters in the engine compartment, especially with twin engines.

I would suggest you contact Dana Marine and ask to speak with Bob, or perhaps Dana himself. They both are very helpful and would be more than happy to assist with your installation needs regarding fitment. From my own personal experience, they are great guys and take extreme pride at making sure their customers are completely satisfied with the products they purchase.

Normally, I would post a link for you to there website like KEPP did above in his reply, but I think it’s against the forum rules. You see, I started a post similar to this but instead of asking about exhaust systems as you are, I was simply sharing my enthusiasm about mine, and in doing so recommended this exhaust system to the OSO community. Somehow, I believe my post got misconstrued, and then it simply vanished of the forum altogether about 2 weeks ago. So, for now, just look them up on the internet: Dana Marine Products.

I believe this site was setup for boaters to share information and experiences with each other. Since you’re asking about performance gain as one of your goals, I feel there is nothing wrong with providing this link that I stumbled upon in my quest at finding the perfect exhaust on a budget: http://www.youtube.com/watch?v=7qThXGeJxkU
This is a cool youtube video showing some very nice boats, marine accessories, and a brief dyno pull made using the Dana Exhaust/Raylar kit and the results. Apparently this combination makes some serious power and may be of interest to you.

rgrgoog, I hope you find this helpful in your quest for the perfect exhaust system for your setup.

Good Luck and happy boating!
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Old 12-23-2011, 06:21 AM
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what did you end up with? I need a set for 2 procharged 502's in a '95 29ft fever. PM me if possible please
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Old 12-23-2011, 08:53 AM
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I am going to have a set of Stainless Marines put on after the Holidays. My Port Engine is making a loud metal knocking noise and we are pretty sure I blew and Exhaust Manifold gasket so the engine has to be pulled anyhow. I will be getting Rid of the CPTs Call/Silent choice setup. I really have no need for it around here and it is just added weight anyhow.
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Old 12-23-2011, 11:08 AM
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Originally Posted by onelightmind
what did you end up with? I need a set for 2 procharged 502's in a '95 29ft fever. PM me if possible please

you need to make sure what ever system you go with will clear the Prochargers .... I am running EMI's and the intake Bell that mounts to the procharger intake had to be trimmed to fit ...and also the blower itself has clearance issues with the exhaust (port) manifold .... I am looking at at new exhaust this winter and will post when we mock everthing up ....m
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Old 12-23-2011, 11:34 AM
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Stianless Marine -- you can find them used for real good prices, and they are pretty close to the ones I'd consider used because of the design.
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