I have a set of new Zul blower motors with CMI through transom 4.5" tails. The water comes in through a jacketed pipe at the very end. The boat is to loud for me to take the kids out, so i am sad to say I need mufflers. I have been looking at CMI's sound eliminations clamp on's, Gibson clamp on's, Aqua Power LTD clamp on's and GGB's inserts. What experience have you had. CMI's tend to be the priciest, then Aqua's then Gibson. GGB'S are 1/3 the price of the more expensive ones. I am just not sure if they work. I also don't want it to be to quiet. I also considered the turn downs but have heard varying experiences. Any help as always is appreciated!

i personnaly wouldn't use any insert with a hi-perf big inch engine...exhaust gases need volume to expand...get the biggest clamp-on you can tolerate

I have gibsons and like them. I dont think I would do the slip in kind.

How quiet are the Gibson? What power are running and was there any loss in rpm?

GGBs are great and simple , they really killed the pounding on mine , the water is dumped right near the end on mine also I was very surprised how it tamed down without power loss .

+1 the GGB's take the bite away but still sound good. No power loss and they're cheap. Mine are 4 1/2 inch clamp ons

I don't think GGB makes clamp on's anymore, they only have the inserts listed. I am also considering the Drew Marine ones.

I'm pretty sure they still make them. I just bought mine a couple months ago. They sent me a price list of everything and they were on it

I had some Gibsons on my blower motors only 650 hp def quieted them down significantly.
Only problem was it caused me to blow 2 drives in one weekend.
Put them back on shelf! Got some headsets!!
Those damn muffler Bearings

Gibson PN# 110003, 4 1/2" clamp on. They didn't list a price.