Back in the day used a Donaldson Muffler on my 98 12v do a forum search and you should find some old posts.
If I understand him correctly he has a straight pipe and wants it even louder.
I don't mind going louder, I also wonder if each generation of truck has a inherent exhaust sound. Seems like I hear different tones from every truck I see (idling, acceleration, being passed on hwy). I think maybe those with the huge echo chamber tips are the loudest. I might be searching for a tone that's not available to me. I grew up with Cherry Bomb mufflers on all my gas trucks, I miss that sound.