[Tx Firefighter]

A simple crossmember swap will get you discs off of any 71 through 87 truck or 71-91 Suburban.

Or, if you want to lower the truck, just buy drop spindles from whatever vendor you choose and put the rotors and calipers on them.

I'll be posting a disc brake swap article for the FAQ section next week or so. I'm right in the middle of this right now on my Suburban.