I was running these Corsa muffled tips on my boat last year, and I like the looks of them and the way they knock the edge off the sound, but I am going up in power with my new build (489 BBC, mild hyd roller, AFR 265 heads) to around 575 HP conservatively, and I want to be sure that I am not going to be restricting exhaust flow too much. I am going to be running a set of switchable diverters thru the prop off of the collectors on the Lightning headers, so that may actually provide some additional exhaust flow thru the prop as well as the tips when the diverters are open. FWIW, these tips were from a Powerquest 260 that was factory equipped with Quick N Quiet and a 450HP blue motor.

Thanks for any insight on this.

No one is running anything like these? Pretty much like the ones with the flappers...

Those Corsa muffled tips will probably cost you 1-2mph at WOT.

I could probably live with 1-2 mph. Now 4 to 5, that could be a problem.

Are the ones with a removable muffler insert a better way to go? I have a set of those as well, but they don't look like they would be as effective at muffling the sound. Kind of like the more "massive" look of the Corsa's as well.