I have dual 3" in / single 4" out and exiting at the stock location and had no drone till I put on pacesetters and took off my cats.

it had as good throaty sound and at WOT would scream

 

Which Flo-Pro hd big Oval Muffler did you install. Are you running Dual or Singles

 

Flo Pro 2503 is 3", dual in/single out and the 2504 is 3", dual in/dual out. The 2504 is louder

 

I Have the flowmaster dual 2 3/4 in, One 3" out just before the rear Pass tire. It doesn't Drone too bad, but the other day I had a 4000+# tractor on the trailer and it droned me to death, I want that Beeeaach Gone soon. I think I'll do Magna flos and dump back by the bumper Pointing straight back. Whos got the best price's on them? Thanks...

 

I have a 99 GMC Sierra, and have been through 3 setups myself.

1st was a 14" Magnaflow, then the large SUV Magnaflow, and now I have a large 3" in dual 2.5" out DynoMax.

All of them had interior drone.

My exhaust is dumped behind the passenger side rear wheel. I read in this post that dumping the exhaust behind the wheels makes the drone worse. Is this correct?

Will adding a bullit muffler in front of the main muffler decrease the drone?

 

I have been calling several muffler shops and they all tell me the same thing as "8MC" said the Flo Pro is the best for eleminating the drone but the 2504 will make it louder but will still not have that drone in the cab. They also said that on that motor you should either dupm it out the corners of the be or straight under the bumper.

I am going to try in the next few weeks. I will let everyone know how it works out for me. Hopefully I ma not wasting more money

 

If you put a cam in it, it will get rid of it

 

I've had a magnaflow on mine and the sound was great, but there was still some resonance. I now have a hooker areochamber and there is none. I love these, they are cheap and sound awesome.

 

Corsa would get rid of the resonance for sure. The HD has the same issue as the SS Silverado. The resonance is caused by the size of the pipe for the most part as well as muffler design.