I have a set of stellings headers that look like this for a SBC:



This is not going through the transom, they will be going OVER it. I know that the cops on Lake Monona here in Madison are nazis, so I am trying to figure out how I'm going to make these work. I need to be under 90db. Ideas? Would prefer to shove things INTO the header, instead of clamping more things onto it. They already overhang by a large amount.

Are they waterjacketed headers?

Yes, fully jacketed. Beautiful craftsmanship. The water enters via a log below the individual runners, and exits at the tip of the headers. The ID of the main collector is about 3.5", but the problem is the opening is not totally round thanks to the small .5" diameter water exiting pipe. It is a round collector, but at the very end there is a small pipe for the water to exit.

short of slip on mufflers which are probably too long for your application. I have a set of stainless marine manifolds with long ( not near as long as yours) semidry tails water exits right at very end of tail that I'd be willing to work out a trade on as you could then run slip ons can provide pictures. I run on the gulf coast so noise is not a problem yet,,,,,,

I have seen some gatlin gun silencers installed inside the tubes but it can get pricy!

you're going to have a hard time making those quiet without adding somthing ugly (matter of opinion) to them. You could get some bolt on's take them to a quality metal shop have them shorten up your headers and weld on the bolt on's.

Try rex marine they may make a slip in muffler for them. The best set up for them used to be super trapps, I dont know if they still make them. Also if you leave them that long you should use braces from the collector to the block.

I highly doubt any slip in muffler is going to get them below 90db.

So there is no way to make these quieter to any real degree? Where are you supposed to use them? Seems like every lake I can think of has an 86db limit.

Hrm, this is what I've come up with so far:

http://www.predatorraceproducts.com/...-insert/Detail

DIY

http://www.jalopyjournal.com/forum/s...baffles&page=2

http://www.r1-forum.com/forums/showthread.php?t=228577

http://www.jalopyjournal.com/forum/s...ght=lake+style