Welcome! I'm working on a '51 3600 as well. My budget told me not to go the disc brake conversion route, so I have "upgraded" my front brakes from the original Huck to Bendix (12" x 2"). I acquired a pair of '53 backing plates from another forum member, then purchased new cylinders, springs, adjusters, shoes, drums, etc. An easier option would be to find a '53-'59 donor truck and get it all in one shot, but nothing was available out my way. I also changed out my original master cylinder for a new dual-circuit master cylinder (no power assist). I can provide the vendor/part # info for the stuff I bought if you like.
