That situation is becoming more common. In New Hampshire they recently outlawed switchable exhaust. I was told that on Lake George, in New York, they will issue tickets for running straight exhaust. The only place in my area that still allows straight exhaust is the Hudson River and that only on the River, not in the local Creeks or in any marinas. The World is becoming a quieter but less interesting place. LOL.

I've had the water sheriff give me a hard time with mufflers. No tickets yet though. I do run without mufflers on Lake Huron. I was doing some tuning and making some WOT passes to check things out, left my family at the dock while I got crazy. They said that even after they couldn't see me they could still hear me and loud.

I had a baja with a 7.4 and switched from the muffler tips with flappers to the straight through tips and it sounded a lot better! IMO not that much louder driving, just deeper and more throaty. Couldn't really give you from the dock comparision. Where i boat, no noise issues.... Make sure you seal them good. Friend had the transom from the exhaust holes down rot out from changing tips!

I changed my Baja 272 from muffler tips to 10" angle cut tips with internal flappers. At the time the engine was a 454 Mag EFI. It got the sound out from under the swim deck. Made it sound a lot better. Now I have a Custom 496, 600HP with a 741 cam, is really sounds awesome. Of course I'm in the South East in VA. While not "Deliverence" country, folks here seem to appreciate a good sounding loud engine. State line cuts through our lake and I've been through drunk stops in VA and TN, and the officers seem to like it too, although VA does have a law against switchable exhaust and does have a db standard. We're just lucky I guess. We believe "IF IT'S TOO LOUD..... YOU'RE TOO OLD":Score-101010:

I usually boat on Mead , Mojave and Havasu...this last summer , got pulled into an OUI inspection , passed everything , until the pistol packing hermaphrodite ranger said let's check him for noise . Long story short , with mufflers , Imco Gattlins , 1.5 dba over , I got a nice ticket .

I doubt you will see any difference in sound. A stock 7.4 without any mufflers should still pass a db test.