Based on your avatar are you talking about a challenger? If so, is it a 73 or 74? If it's a 73, that's what I have, and I am in the process of doing this right now. You do not need new bumpers (if it's a 74 then I believe you do), only the 70-72 brackets. One thing I did have to do with my bumpers is fill the top holes on each bumper where the bumperettes bolted on, but I just had this done ($10 each hole) when they were chromed last month. We have already test fitted the brackets to the bumpers, and the holes line up just fine.