My brother and I once made a whole exhaust system out of driveshaft tubing and 3 1/2 inch tractor mufflers with the baffles punched out. Any money we saved by doing it ourselves was soaked up in the first of many tickets, but we were heroes of the street for quite a while, and the sound was incredible! 440 Magnum, 4spd. in a '64 Dodge 2dr.