Does anybody run GGB exhaust inserts ?. The inserts would be for a pair of merc 420's w/ 4 inch Gil's

They work great & cheap .

Yes I run them and really like the sound. I have short ones and do not think I would pass the law but love the sound. Longer inserts may pass but I just wanted to take the edge off open exhaust.

I run them, too, because there was no room for mufflers or stock turndowns on my boat. The inserts quiet the exhaust just enough that the noise police has not given me a second look. I usually drop down to one engine when they're around as well.

Same here, they take just enough of the bark off so I am left alone by marine patrol.

They look restrictive?? Do they hurt power? I was thinking of just taking the bite out of my stock 496. These look like a possible solution.

On my stock 496HO motors, about 1 mph. With the modifications, about 2 mph. All in all, I will give up 2 mph to not be harassed by MP, and they are plenty simple to remove and install for poker runs.

I've got them in my twin Mercury 700 SCI's exhausts. They work great. No issues.

Thanks for the comments , I am going to order a set in the midsize length .I can always cut a ring or 2 off if too quiet

How many rings are you guys running?

Sorry to hijack stick. I figured it was all good info.