Author Topic: 312 stinger thru hull exaust HELP  (Read 1948 times)


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312 stinger thru hull exaust HELP
« on: November 16, 2013, 09:19:44 am »
Good afternoon all;
I am the current owner of a 312 stinger, this is a STOCK boat w/twin 454 (330 hp)  motors & alpha drives. I have ben a boater for over 30 years.
The info I am looking for is: Adding thru hull exaust to this boat.  I am looking at a sielent choice style exaust.
I can aquire the" Kits" (tips, diverters, hardware, ect..) But the problem I see is I need to make the exaust exit ABOVE the rub rail. If I use the "Kitts as supplied the exaust exits below the rub rail and thru the hull & swim platform.
Question: Is there a riser or adpter to rase the exaust exit to above the rub rail ?  I know this sounds like a stupid question ...But I want to do it corectly. (years ago I put thru hulls on a boat low near the waterline...I dont want to do this like that agan....too many issues!)


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Re: 312 stinger thru hull exaust HELP
« Reply #1 on: November 16, 2013, 03:39:23 pm »
To answer you questions:
First the silent choice exhaust can be of many manufacturers. I have "Shotgun" exhaust on my boat and it opens up around 1200-1300rpm. there are lots of other types that are vacuum operated or solenoid operated. Check out the used parts section you might get lucky
As for the exit of the exhaust, I recommend that you keep it below the swim platform. I have mine below on my 390 and it is still quite loud! On my 260 the exhaust was above the swim platform and intrusive. It looked and sounded cool but I like the pipes below the platform for aesthetics and for sound. These were unrestricted tubes for small blocks and quite loud!
On the 390 I have big blocks and the exhaust has vacuum operated flaps on the outside tips. You could do this as you only need a set of stock Mercury manifolds, as that is what I have on my boat, and the pipes are held in by short sections of rubber connecting hoses that go to the stainless tips.

My 260 with exposed tips:

My 390X with tips exiting just UNDER the swim platform

Notice how clean it looks with the tips underneath and they don't stab you in the back when your sitting on the platform

This one you can barely see the exhaust tips (sorry I don't have a closup picture of the tips) but they are just above the water line and under the platform.
« Last Edit: November 16, 2013, 03:56:56 pm by stinger390x »