looking for some suggestions . .
My boat is way too LOUD! 4 x 4" exhaust wide open with twin 383 SBC . ..
I don't want to add external mufflers and would prefer to retain the original backslashed tips, they just look so cool!
So I want to add mufflers internally, I have about 12" of length that I can easily utilize.
Suggestions of what is really effective and works well.