CMI = Small Block Performance!!

Old 07-13-2011, 08:54 AM
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Originally Posted by 4mulafastech View Post
What is the reason for the need to remove the baffles?

CMI claims each header weighs about 20 lbs, so the weight reduction will be nice. Do you know what each cast iron manifold weighs?

I know not to expect big gains in power on a stock powerplant, but long term I plan to make some engine modifications or go to new engines all together that will really make use of a good exhaust. Although, it would be nice to talk to someone that has made the swap on the 6.2L to get their feedback and make sure there were no issues with installation. I wonder if they have actually sold any of these headers.

Each manifold and riser (cast iron) is around 110 lbs maybe more I forget its been a couple of years since I did mine.If you go through hull only and eliminate the prop exhaust you have to take th (8) pinwheel baffles out,They are very restrictive I picked up 200 rpm and almost three MPH when I did it.No gains over stock just got me back to 5100.
The reason I went with Imco was I needed exhaust and it was cheaper and better than Merc.Unless you are going to go into the motor or procharge you are not going to be able to do much with a stock my opinion
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Old 07-13-2011, 09:45 AM
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wowchad, thanks. Mine does not use S pipes and will be going straight out the transom. So did you buy the E-tops? Let us know how they work out.

Expensive Date, thanks. Man, that is heavier than I thought! That will knock off over 350 lbs back there. Did you weigh your Imcos? How much louder is it with the baffles out?

Oh I will definitely go into the engine. By the time I actually get around to upgrades they will have a lot of hours on the meter.
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Old 04-17-2012, 07:01 PM
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I have a Fountain Fever 29' with twin 6.2 MPIs and Silent Choice. Is there a model that is a bolt on with this setup? I do not want to give up the Silent Choice. I would love to hear performance difference from someone who has the CMIs on stock twin 6.2s.
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Old 04-18-2012, 09:24 AM
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Originally Posted by 4mulafastech View Post
are you aware of these headers being applied on a stock 6.2l mercruiser and, if so, what were the performance gains? Thanks.
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Old 01-26-2018, 01:48 PM
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Update - doing an LS swap and the exhaust is different!
So I'm selling my Polished SBC CMI E-top headers in the classifieds right now if anyone is looking to save $$ on a low, 60 hour Wisconsin freshwater set of beautiful exhaust headers.
Chad Salter c/o Tewco, Inc. Franklin, WI

Last edited by wowchad; 01-26-2018 at 01:55 PM. Reason: grammar
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