I did this too. I used my '74 bumpers AND brackets. Redrilled the front brackets like mentioned. I posted some pics in this thread: Snug Your Bumpers Up Cut, overlapped then welded rear brackets to shorten them up. I then used the nice chrome bumperettes to fill the holes in valance where those huge and ugly 5 mph bumperettes were. I had to make the mounting brackets for those as no factory bracket would allow the 70-71 bumperettes to line up nicely on the '74 bumper. I have sets of the cuda bumperettes and mounting brackets for them if you need. I thought maybe cuda stuff could be modified to work but never used them.