Pypes Turbo Pro

I just had the Pypes Turbo pro mufflers installed on my 72 Duster with a healthy 340. These replaced my Magaflows. I only bought the Pypes because of their promise to "elimate drone". Unfortunalty the drone is worst now than with the Magaflows, but at a slightly lower rpm. I also have resonators installed but they didn't help all that much. I also have X pipes. I guess I need to think about adding a J pipe.