bypass cat and muffler???

It is a bolt on thing. But you need all the parts like the fender, hood, bumper,bumper mounts, grill, and the rad support for it to work. Could also change to a 70-72 duster front end. A 70-72 Duster/Demon rear bumper and mounts can also be swapped on with a little work to the mounts. IMO it looks a little better and the bumpers are a lot lighter than the later ones.