The magnaflow on my Denali drones at 2200 rpm. Unfortunately that is right where my truck cruises on the highway. Sounds beautiful around town though.

 

I BELIEVE THIS IS TRUE, FLOWMASTER 50 SERIES IS ONE OF THE QUIETEST I HAVE HEARD BUT, ACCORDING TO THIS SITE THERE ARE SOME PEOPLE THAT SAY IT HURTS YOUR PERFORMANCE??? I USED TO HAVE A 50 SERIES ON MY 94 AND IT SURE WAS QUIET INSIDE.... MY .02

 

Ive had a 50 and a 40, got alot deeper sound with 40 series 3 in 3 out dumped, the 50 was a 2 in 2 out didnt like it. I didnt notice a performance difference in either muffler.

 

When I had my Lightning everyone on the Forum talked about possibly losing performance with Flowmaster (I had a Bassani so I didn't care). But one guy tested a before/after and ended up almost exactly the same as with one of the best exhausts. As far as a performance loss with mine, I'm not sure, I should have dyno'd before/after, but if you look at the numbers in my sig (this was without HPPIII), there higher than I think they would be stock. 280hp on an all-wheel dyno from a "325hp motor" seems pretty good. Must be the 40hp I got out of the Flowmaster (yeah, right!). The butt dyno shows more power, but anything with a growly-deep rumble usually makes you feel like you're going faster.

Oh, and don't confuse a 50 series on a 4.8, 5.3 or any other motor when compared to the 6.0. I understand the sound the motor produces isn't even close to the other LSx motors and is much harder to "tame".

 

after running flowmasters for most of my younger days, i finally got tired of the drone at speed, so i ordered up a Dynomax HD RV muffler Jeg's part #289-17789. it is absolutely perfect in the cabin at every speed with a slightly louder than stock external sound.

i highly recommend this muffler. i even picked up noticeable power over a 2 chamber flowmaster with a dump and equal sized tubing. i used to think i had to have a stainless exhaust, but i painted this aluminized system with high temp silver and it looked just as good after a year as the day i welded it up, and i only had about $100 in the muffler and tailpipe tubing.

 

Thanks for all the input guys, but I am looking to keep the noise levels down to stock levels, and I don't think any aftermarket exhaust will be able to do that. So as long as no one sees any issue with the location of the mufflers being crucial to their noise reduction ability, the dual stock idea may have some merit. I guess I can give it a try and let you know