SBP drums to SBP disc parts list

Any master cylinder you can bolt to the firewall should work, if the brake rod fits in the piston. I used a 2-4 bolt adapter plate and a newish 2-bolt alum MC in all my old Mopars (95-99 Breeze ABS, 7/8"D bore). An adjustable proportioning valve is best and cheapest ($28 ebay).

In the original SPB disk question, I didn't see spindles listed. That is the hardest part to get since must be factory, i.e. from an old car.