Offshoreonly.com - Whats your thoughts on CMI headers?

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What 44 said, the dual bolt pattern with cool collar are the ones to get, or GenX direct replacement for the 525,600,700, funny how people bash them that have never owned them,

for a stock 496 total waste of money. especially for a heavy cruiser boat with inboards and if it has a muffler box. ??. Your prop options are not that good for any performance gains anyways.

Quote:

Originally Posted by mnm99 (Post 4681896)

Thanks guys. I have no Idea about the reliability and thank you for the input.. It wouldn't be going thru hull either. Just a replacement for stock. Yes it's a 340 cruiser with V-Drives. I'm sure I won't go the header route with this boat the more I research, I was just seeing if anyone ever used the CMI. Within a couple years I'm hoping to be in a gofast like you guys.
https://cimg3.ibsrv.net/gimg/www.off...e36b46dbfd.jpg

Nice looking boat you have there. Like others here have said you would likely see little if any performance gains going to any hot rod exhaust system. But I do understand where you are coming from. Many years back I had a 25 Sea Ray Sundancer with a 454, retrofitted a set of Pachanga Vernatone mufflers and thru hulls into it, sounded like an old 396 SS, cool as chit. Did not go one MPH faster but was a real conversation piece, and made me smile every time I started it .

Quote:

Originally Posted by Wildman_grafix (Post 4681887)

I agree the E-tops are not much more performance then a better design manifold. The KE you are talking about if you see a cut out are basically long tube headers.

But if he just has a 496HO I doubt he would notice and for that matter I have dyno sheets that show the KE lose some mid range on a small motor.

If if I had a staggard boat and needed to buy I would buy the KE’s and paint to match.

WG,
That's why I want you to paint my KE's I have in garage!
Thanks,
MD

You will most likely see ZERO power gain on a stock Mercruiser 8.1. They do look cool though.