I've got hooker 2 inch headers and 3 inch exhaust to the axel and 2 and 1/2 out the rear bumper on My 67 GTX.H pipe.(flowmasters 40,sounds great) 440 stroked and bored to 498. I have that damn drone at 45 to 70 mph ...not real bad..but there...if You figure it out..let Me know. I have zero floor insulation and will give that a shot. Thanks to all for their input