Today I had a muffler fall off my boat in 100 ft of water. I have Stainless marine 3 exhaust with 5" tailpipes. My motor made over 1100 hp last time it was on the dyno and I have been running GGB clamp ons with a internal flapper, it actually idles BETTER with mufflers on it than w/o. GGB is back in business again BUT they are NOT making anything close to what I have so they are out of the question, looking for advice, and opinions as to what is a "good" muffler, that can knock the noise down and is actually in stock somewhere as I have to buy something by next wknd for hot boat party in Mi. My mufflers had internal flappers so If I can't get new mufflers by Fri I have to find 5" flappers for now, Smitty

I talked to Hpi/aquapower in Ohio, they can ship me a pair of 5" mufflers today/Summit in Ohio also has Gibson 5" bullets in stock for 300$ less, can't find many real world results on either one , anyone have any input?

My buddy has 4.5 inch clamp on gibson bullets on his blown 598's, stellings headers and dry tails until the end, water dumps in at end of tailpipe. Much quieter than my stellings/dry to tip setup with no mufflers. His boat has a cool sound, quieter and deeper tone. I dont think he's ever ran without them, so cant say anything about performance.

Smitty, I have a used set of the original GGB mufflers. They were on a 6" tail pipe. I don't know how you would make a sanitary fit to your 5 " pipes.....However, that's the best I have to offer.

I use CMI clamp on mufflers. I like them but dont have any experioence w any others. Call CMI

I have a set of 4.5" Gibsons and haven't noticed any reduction in power, although I'm only pushing 700hp. They make a significant reduction in sound levels, without them the sound is deafening. I just moved my rubber flappers from the tips to the mufflers.

Did you ever data log with and without the GGB mufflers?

Not really, boat was stupid load with open exhaust, burbled and ran like crap at idle, the mufflers straightened that right up. I did do back to back runs though back when I only had 945hp and boat ran 92.5-92.7 back then with and without the mufflers, Smitty

Just curious, I'm seeing the wideband pulling out 100 lb of fuel at 5000rpm with the mufflers on, after being tuned without mufflers. Never had a problem with the idle but it is loud.

I can tell you that my afr's on the dyno that were mid 11's or so turned into high 10's/low 11's in the boat and I re-tuned it to about where it was BUT it has alwayss been richer in the boat every time compared to the dyno even before the mufflers so yes, I did pull fuel out too. I never botehered to check the afr's with open headers as I will never run without mufflers, I used to love loud **** now its just gives me a headache, I hear enough noise all day at work!!