I am looking for thru transom mufflers for my custom 600HP supercharged and intercooled engine in my Scarab. Looking for the least amount of power loss while still losing some db's. Is this possible?

Any help would be greatly appreciated.

CMI sound eliminations.

Check out the cyclone series thru-transom silencers and clamp on silencers here
They're sure to keep that beast quiet.

I installed the Tomahawks by Hardin. Minimal HP loss and VERY quiet. I installed the caps in the ends so the exhaust is directed down.

I am currently looking at CMI Turbo Tips. I have heard minimal powerloss but keeps the dbs in the danger zone of illegal.

I'm liking the donkey dongs (turndowns) more and more. Saw several sets in use at the shootout. Dave Scott runs them on all his boats. Keeps the transom clean, nice and quite around the docks and no wakes, and no power loss.

These are the ticket to not getting a ticket.

On a pair of Merc 600's, they robbed too much HP. They are very quiet around the docks, though.

You shouldnt have lost more than 50 RPM max.

What year were the mufflers? Old or new style?

We have sold several dozen sets and not one complaint. I just was wondering what the issue was.

Go with the turn downs then. Thats what I run too!

2006. The setup was Merc 600's in the first F-4. They did their job in terms of noise reduction. Very quiet at idle and around no wakes and docks. Even when they opened up they were pretty quiet. Blower whine was much louder than the exhaust noise. I don't remember how many RPM we picked up by removing them but they did cost a couple of MPH on the top end. I'm not knocking them. If you are looking for a quiet muffler that you don't have to worry about wiring or air lines to switch them on/off these are the berries. They did rob a bit more performance than we would of liked to have seen, though. They were replaced the following year by what would become CMI's Turbo Mufflers.