I had a drone on my 6.1 Hemi '69 Cuda with full TTI H Pipe exhaust and Dynomax Super Turbo mufflers. Plus the exhaust was quite loud when cruising.
I installed a set of Flowmaster Resonators 15150S. Drone completely gone and exhaust much quieter. Very happy.
These resonators are a straight through 2.5" design with a closed tube alongside. Photos in this FABO thread http://www.forabodiesonly.com/mopar/threads/srt8cuda-build.218445/page-27
Jim

1970 Superbird 440-6bbl, auto
1969 Barracuda 340-4bbl, FB Formula S auto
1969 Barracuda 6.1 L Hemi, 5 speed, Convertible
2022 Can Am Spyder RTL