Another thing to consider is the axle offset from the backing plate flange. Early 9"'s had an offset of about 2 3/8" and used a narrow brake shoe without self adjusters. Later 9"'s had an axle offset of 2 1/2" and used a wider brake shoe. I can't remember the exact shoe width, but offset #'s are accurate. The reason this may be a concern is there are lot's of aftermarket brake upgrades for the later axle, but very few for the early axle. Even a lot of the late model factory disc brake setups will bolt on to the 2 1/2" offset axle. The change I think happened around 1963 / 65.
