I'm not even running a prop valve on my '66.
'72 up manual disk master cyl, small res to rear brakes. big res to fronts.
Worked fine with factory 8.25 drums and now with Ford 8.8/Explorer disks.
Stops great.
If I am using 73 and up disks with 10” rear drums I don’t either. Toss in the factory distribution block for 73 and up and it works as the later factory systems were designed.
