CMI Exhaust

Does anyone have any exspirence with CMI Sport Tube Exhause on a 496 HO? I have heard 50-75 horse power and nice mid range power.

I was looking at the Dana Headers and the CMI E-Tops. Decided on the Dana, best bang for the buck.
I know of a couple 496 with the sport tubes and they saw good gains, but no documented testing could be found on the CMI's

I've installed some of the sport tubes on 496s. Pretty much all were a 3-5mph gain on the top end so 50-75hp seems about right. A lot of times people had to step up a prop size too. Also the boat sounded a lot better, which is the biggest benefit