1999 GMC Sierra 1500 Ext. Cab (old body style) 305 (5.0 liter) single exhaust
I just had a Flowmaster 40 series Delta Flow put on my truck. It is a single in, single out, offset muffler, with 3" inside diameter on both the inlet and outlet. I also opted for a 3" aluminized tail-pipe and a 3" to 3.5" chrome tip. The original piping was 2 3/4" outside diameter. I am pretty happy with the final result. The in cab resonance is barely noticable at idle, definitely noticable when accelerating, and not bad when just cruising. The outside tone sounds really great, especially when I step on it. Idle has a nice outside tone as well. I also was trying to decide between the 50 series Delta Flow and the 40 series Delta Flow and I probably would be just as happy with the 50 series. I'll post in a couple of weeks to let you guys know if the in cab resonance is driving me nuts. Maybe I'll post some pics, as well...