kelsey hayes part and proportioning valve

Im assuming it would be less modification to use the original stuff from inline that your speaking of than using an adjustable one? Also, I THINK I read somewhere on here that you can use the prop valve from a 1973-76 disk drum car also, even though its a single piston type system?

The newer combo distribution valve with the Texas hold off as part of it does not fit well on the earlier A without modifying the line sets. Seems much easier to plumb in a adjustable unit.