The '57-'59 Ford 9" is very close in overall width, as are some later 8" & 9" Fords, but I know of none that are a "bolt-in", as the spring pads are off an inch or so ('51 is 42" center to center, '57 and later are 43" or more). Add the fact pinion angles might be different, so spring pad replacement/movement should be planned for a good installation, IMO.