Kelsey Hayes disc brakes

The only thing different about manual and power k-H system is the booster and maybe the pushrod for the master cylinder.
Accordering to the '69 Chrysler Master Tech booklet on brakes, all K-H used Master Cylinder p/n 2808600.

You can read yourself up on brake systems and how they work courtesy of Ma Mopar
Several good booklets from the 1960s and 70s in the collection
http://www.imperialclub.org/Repair/Lit/Master/index.htm

Conversion to BBP requires machining. See sticky at top of this subform if you really want to get into that.