Flowmaster drone solved.
Im using long tubes, 2 1/2" X pipe, 14" Pypes Race Pro mufflers like a Magna Flow, stainless straight thru with packing, tailpipes out the back with tips. I had a wicked drone at cruise. I tried chambered, no better. I finally welded into the tail pipes Helmholtz tuneable resonators. No drone what so ever and the idle is quieter also, until you stand on it and it gets heard. They do an amazing job.
Im using long tubes, 2 1/2" X pipe, 14" Pypes Race Pro mufflers like a Magna Flow, stainless straight thru with packing, tailpipes out the back with tips. I had a wicked drone at cruise. I tried chambered, no better. I finally welded into the tail pipes Helmholtz tuneable resonators. No drone what so ever and the idle is quieter also, until you stand on it and it gets heard. They do an amazing job.