[Cuttin up]

My experience, back in my mini truck days, was to run a long 3 chamber muffler to quiet the drone in the cab. I believe the 40 series is a 2 chamber and coupled with large diameter pipe, drone is gonna be awful. I have a 84 cutlass with an ls swap running dual 3 inch pipe and two 40 series flowmasters with it exiting behind the rear wheels, and the drone in it is terrible at about 40 mph. But it sounds damn good though.