Having been there and done that I can speak with some authority on the subject. the axle width is the same from 1929 (I think) to 1954 share the same dimension. The earlier ones have a smaller dimension king pin and bushings up to about 1936. From 1937 and later the king pins and bushings are the larger diameter. The spindles are of similar size and shape the only difference being the diameter of the king pins and bushings. As for the disc brake conversion, 1967 and later Chevelle and Camaro discs will work without modification except for spacing of the bearings to make needed clearance for the discs. I have done this modification several times, and it works great. To clean up the look of the disc installation I have made a mount bracket for the caliper which is an easy item to make, the stock bracket can be used as is if you want to save a bit of fabrication. Good luck, it is an easy conversion. As for Discs or Bendix front brakes and Huck rears, it works fine as long as you use the residual pressure valve for Discs, the Bendix and Huck brakes use the same residual valve.
