street force headerscompetitionheaders truck ... force headersfootnotes 1 thissystemuses21/4 o.d tubing we recommend ... using either the supercompetition aero chamber maximum flow ... or turbo mufflers in a 21/4offset inlet/center outlet ... configurationsee page 62 for complete muffler ... the part number when ordering 3 factory 4 wheel drive 4exhaustsystems can also ... be fabricated using either hooker supercompetition aero chamber mufflers ... maximum flow mufflerssupercompetition turbo mufflerscompetition ... type hooker mufflers 5 not legal for sale or useonvehicles originally equipped ... converters for racing purposesonly 6 comes with h-pipe/balance tube ...