A friend and I put side exhaust on an old boat I had, and wow, extremely loud!! It had a 350 in it, but people would always ask what it was. You should have seen the jaws drop when I told them it was just a 350!!! I bought the tips on e-bay for something like $100, 4" SS tips. I then bought the Trident Rubber Exhaust Hose. We disconnected the 90* turndowns and turned them sideways, went 4" lower then where they came out of the risers. The turndowns are like a 3 1/2" but the 4" hose will clamp down on them. We plugged the Y pipe with some plumbers fittings from Home Depot. Homemade jobber for less than $225! Took about 3 hours to do. The worst of it was taking a 4" hole saw to the side of the boat right at the waterline!!

Not sure if anyone else has noticed this, but I'm not a fan of the sound of side exhaust at idle. From the shore, you only hear one bank of cylinders and it sounds -well- weird to me. Not as noticeable up and running, but man at idle.... I'm not a fan.

I ran the inline silencers 410-285400 they would quite it down nicely