I went thru a journey with drone with my 67 GTS. After the engine rebuild with a milder cam close to stock I got a brain rattling drone. Same exhaust system as before. Tried Magnaflow, Dynomax Turbo and finally Dynomax VT which are suppose to be drone free but only decreased the drone 12db. I had to finally install branch resonators and that took care of the drone. There's a thread here on journey and how I did it.. http://www.forabodiesonly.com/mopar/showthread.php?t=202506
