I've got 2 1/2 inch dia, 24 inch long stainless steel Magnaflow mufflers on my 360 Cuda. Interior resonance is really bad. I've been thinking of adding resonators to my car. I'm not sure if they will help with the cabin noise. I really like the way the car sounds, but the exhaust drone gets old. Does anyone know anything about this? Would I be wasting my time and money?

Reportedly they do & I'm going to use them in an upcoming build w alot of beef. Use em . Also an X pipe is good for noise reduction and "Helmholtz Resonators"

I run two sets of mufflers on my Jensen, two large turbo mufflers up front, and two Dynomax Bullets out back as resonators, I love it.

I have two 3" Flowmasters in tandem in my motorhome, very healthy 360, 1 3/4" long tube headers, 2 1/2" collectors, they Y into one 3" single exhaust.

It is QUIET at idle with a nice deep rumble, sounds like a musclecar when pounded. NO drone.

I love more than one muffler inline...

The mufflers are in front of the axle. I'm just trying to eliminate some of the drone in the car when I'm at highway speeds. It's really loud. Listening to the radio is impossible on the highway.

I'd add some GOOD quality glasspacks at the rear. Most muffler shops that do performance exhaust will stock some good glasspacks. Put some 2.5" ones as long as will fit back there. Be sure to look through them to make sure they do not reduce down internally to a smaller diameter flowpath. I would also use ones with small louvers & have them installed where your exhaust is going against the grain. You don't want ones with really large louvers either. If you use ones with a smooth perf core, you are likely to keep the resonance.

I believe that resonance is a product of each exhaust system, tube diameter, length, muffler design, etc. so basically, each car is going to be different. only way to find YOUR answer, is to experiment with YOUR system.

my experience, on the dakota, I had 2 3" flowpath powersticks by themselves welded end to end running the length of the truck. sounded great! only problem was resonance at cruise. I had the exhaust dumped infront of the axle, it was back under the bed of the truck, not under the cab though.

anyway, resonance may have been a product of exhaust design, may have been because I had it dumped and the sound was "trapped" under the truck.

I added a 12" long glasspack from summit. it's basically the same design as the powersticks, but with some fiberglass packing (the powersticks have none) then I routed the exhaust up and over the axle, and down at a 45 degree angle from the "high spot" so that the sound "shoots" out from under the truck as it bounces off the ground.

killed all my resonance, made it slightly quieter, just enough to notice that it was a little quieter, and kept the overall sound the same.