I ordered a new AC Delco Master Brake Cylinder and decided to not replace the original cast iron Proportioning Valve assembly.
I want to maintain that original master and prop valve look.
I researched a lot about aftermarket prop valves and saw many complaints of poor quality and leakage issues of the brass style replacements.
A few forum members commented that they maintained and kept the O.E. Prop valves./
I also found through searching past forum posts about a vendor that rebuilds the O.E. proportioning valve assemblies and contacted them.
$$$ Pricey but guaranteed for life.
I noticed a couple of members here that have used that vendor for rebuilt brake assemblies.
If needed later on, I will rebuild my O.E. unit.
Thanks again to Toro and 72BBChuck for your input posts.