55.2-59 56 straight axle squarebody hubs

[mgchevyparts]

I suspect this truck build had dealt with the same issues you have. The rear end is out of a later Chevy truck with 5 on 5 so the front kit matches up
The disc kit was professionally made as the brackets are laser cut and any disc kit for this original spindle requires bearing adaptors which are not easy to do without CNC lathe, but I can't find it anywhere and I'm certain you have searched