Trying to Eliminate Drone. Need Another Opinion.

So, I have this long thread on Moparts on trying to reduce the drone in my car. 408 stroker making 500 + hp. I have TTI step headers with a 2.5" X-pipe system from TTI. My drone was between 1500-2200 rpm.

To some up my journey so far, I bought some dynamat and put it on the rear panel and it helped a little bit. Then I removed the 14" long Dynomax mufflers and had 18" Magnaflows installed as they were the largest I could go and that quieted the car down (great), and reduced the drone down to 1800-2000 rpm. The guy who installed my exhaust didn't want to do anything else. After that, I noticed my driver's header was resting on my PS box so I shimmed the engine so it wouldn't contact and that reduced some of the vibration in the car.

I'm kind of stuck at this point. There's no room in front of the mufflers to add resonators as the exhaust pipe centerline is only 2" away from the bottom of the car. So, that leaves me to the rear of the car, past the mufflers, and I don't really have much room to add anything back there unless I get crafty.

I don't have any welding ability so no Helmholtz resonators (all the exhaust shops I talked to had no idea about what they were) and I have to use band clamps. The smallest resonators/glasspacks I found have a 10" case and are about 12-14" in total length. I only have about 11" between my exhaust hanger and the rear of the car so shooting a resonator straight out back may work but may be tight (no exhaust tips). I can add a bend between 45-90 degrees which will give me more room for a resonator; however, it may look wonky.

I'm running out of ideas. Has anyone had experience with drone and how to reduce it? I hear a lot about people using resonators and that's why I was thinking that route, but most of the instances I'm told about were from throwing resonators in front of the mufflers not behind. Is it a lost cause at this point? Any help would be appreciated.

I also don't care to lose more horsepower as I made 520+ crank hp and can afford to lose more.

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