Borla 20-22 F-250/F-350 SUPER DUTY 7.3L V8 AT 2WD / 4WD / 4DR S-TYPE S Silver TipEXCEPT Vehicles with Dual Rear Wheels. This dual 2. 75" diameter into single 3" Cat Back system was developed for use on F 250 and F 350 Super Duty (Including Tremor Models) trucks with performance, sound, style and durability in mind. The muffler is specifically designed to give the 6. 8L and 7. 3L engines the classic S Type sound without any drone. This system can be adapted to the different wheelbases offered by Ford. 140843 comes with the front