Look's like Gaffrig muffler. Don't know if they make them any more.

Switchable Exhaust
 

I spent what I would consider to be Big $$ on switchable as my boat only came with thru hulls and was really far to loud for me for all the idling I have to do up canals and such. Had I known then that I could have gotten turn downs for 1/4 the price, I would have gone that route. Besides the Corsa system, I had to locate two sets of TRS elbows and all the other parts that bolt to the inner transom plates and each engine had two of these. Not as simple as a single Y-pipe. I have Corsa's and love them but keep thinking that when I am on plane mostly have them switched on (loud) and when off plane have them off. The turndowns would be quieter than corsa's switched off and would have NO MOVING PARTS other than flappers. And would achieve the same operational effectiveness for my mostly stock engines. The only drawback is that the turn downs look funny on the back of the boat, but in my case, you really can't see the pipes because of the swim platform I added anyway.

I have had the Corsa system since 2003 and it has worked flawless in my salt water environment well so far, but if they fail, I will go back to straight pipes with turn downs for certain.

I looked into that option too but dismissed it for 2 reasons; I already have the bullhorn going to the drive so only need the y-pipes which puts me at less than $1k cost, and would like the option of running in stealth mode. I know I probably shouldn't make any WOT runs that way but at 2,500rpm pulling a skier it shouldn't be a problem, especially for my anemic little small block.

Glad to hear you're not having problems with the Corsa system; very close to going that route.

Sent you a PM about a set I have for sale