I just put a Hydrovac unit and master cylinder in my 73 C60. That might be something to look into. It only cost $65 for the master from NAPA and $135 for the Hydrovac. The set up looks pretty universal and would be easy to adapt to most vehicles.

Just a thought.

1937 Chevy (converted to 4x4)
1942 Chevy G506 1.5 ton 4x4
1958 Mack B model (on Chevy 1 ton 4x4 frame)
1969 Dodge Charger
1987 K30 Crewcab