Help, I need a 71&up brake proportioning valve

[njsteve]

Anyone have the cast iron disc brake proportioning/combination valve for a 71 and up Camaro/Firebird with disc/drum? I believe the other GM models of the same era use this same valve. The current replacement seems to be a brass valve that looks nothing like the original.

I just noticed that mine is seeping fluid from the red arrow location. Luckily I use silicone brake fluid so no paint is damaged, but it is pissing me off, as well as being a major safety issue.

I dont see anyone selling these anywhere. You can find them for the Ist Gen F-bodies but not the 2nd gens.