I know you all will think I'm nuts, but I'm wanting the quitest exhaust system I can find that doesn't restrict air flow. I'm building a 355 for my 69SS that should be close to 400 HP. It is a 4sp, PS, PB probably w/ Vintage AC. I want to run headers, so they will make a little noise. The car is for the street only so I'm going for low end torque, but want some power up through 6K. I believe I need 1 5/8 long tube headers- but what after that? I want to keep it as quiet as possible. Slightly noisier than stock. Thanks for your help!
John

Then put stock type mufflers on it.

My '67 came stock with a resonator on each side under the back seat and then the crossflow muffler between the rearend and gas tank. It was quiet as a mouse!!

I bet just the crossflow muffler will give you that not quite stock quietness you are looking for and if you pick a modern muffler vs the stock one will also get the flow that you want.

Or go the otter route and run just the two resonators, but I bet it will be louder then you are asking about keeping it at.

Hope this helps.. pdq67

The exhaust system design will also play a role in the quietness. The addition of a crossover tube or x-pipe will reduce the sound considerably.

Get a set of Dynomax Super Turbo "HEMI" versions and an X-pipe. I know a few cars with these mufflers and they sound awesome yet *VERY* quiet. One of the car runs low 10's and if you closed your eyes you'd think a stocker was going down the track.

http://www.boyleworks.com/ta400/psp/exhaust.html
is a good article on quiet, powerful exhaust systems. The Dynomax 17749 in the chart is the "Hemi Super Turbo" that Chris mentioned. The 17734 is a shorter (14" case vs 20"), louder version. Two of these will handle 380HP without significant back pressure (the longer ones will handle 400). The longer ones look like they may be too long for a Camaro or a Nova.

That's why I didn't mention the Hemi mufflers b/c they won't fit where our resonators fit.

I have two 2.5" x 18" under my front seats and two, 2.5" x 12" at the resonator spots cheap JCW Turbo mufflers down each side with an H-pipe and my car still seems too loud with my 406, but I suspect most of my noise is actually "header" noise.

And my 2.5" tailpipes exit at the stock location, right behind the tires..

Some guy's running "Q-Ship" big Buick cars have even "Y'ed" their duals and put four Hemi mufflers, two side by side, under them so that they are "Stealth" stock quiet!!

pdq67

PDQ,

Jim's message implies that the 17734 may fit ok. Only 14 inches long. :D Has anyone tried these on a first gen Camaro with 400+ horsepower?

Peter

Sorry Coach, I was under the impression that the Hemi style mufflers were like 20" or maybe even 22" long and quite thick when compared to a regular Turbo style muffler, that's all.

14" is just 2" longer then the Turbo's I have in the resonator position now..

I did have to watch the inlet and outlet offsets if I recall right so the custom bent connector pipes fit good..

pdq67

Excuse me if this has been asked before, I've just returned to the hobby of building old cars after a long time away playing with newer cars. What do you guys think of Flomaster's 50 series delta flow mufflers? Quiet?

Thanks for all the info; it really helps! Did the stock 69's all have the exhaust exit locations behind the rear wheels? Which is quieter - behind the rear wheels or straight out the back?
Thanks,
John