Some disc/drum masters don't have enough stroke for rear disc brakes. If the pedal it's a rock solid stopping point deep in the stroke you may want to check that out. I know it's theoretically possible but I haven't experienced it myself.
The hot rod has a D150 manual disc/drum 1-1/8" unit pushing fluid to the AMG disc brakes.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon