If a guy has a small bolt pattern 7.25, it may be different. I just literally tried it about 2 weeks ago on my '74 Duster. It has SBP, and the holes in the 7.25 backing plates were off, even if I would have drilled the 5th hole. Also, I would have had to drill the drum, or get a drum that would work (seems a '64 Rambler drum is 9 x 2 with 5x4.5 pattern). I'm just using the 10" backing plates.