Im not 100 percent positive on this because I have not done it. I really think this is a bolt on deal. You would need a 72/73 bumper, bumper brackets and a rear valance. I dont think a 74 used a rear valance, the bumper extended down lower to cover that area. I believe 70-73 used the same rear valance, although the 73 used less bolts to hold it on.It would be quite a bit of work..... but it would be possible with enough time, tools and parts.