KELSEY HAYES PROPORTIONING VALVE KIT SOURCE

Definitely look up the ford part, I bet its still available.
I've wondered about using one myself.
The op isn't asking about buying a replacement proportioning valve, if he can't find a "rebuilding kit"
He's inquiring, asking, about a "kit" so he can rebuild his existing one.

And besides, you can buy repop valves for a Mopar, that you don't have to purchase a Ford designed one.
But as of late it seems the repop ones for a Mopar tend to have defects, that they tend to be leaker's.
It's better to rebuild your old, existing one.
But i have no experience in ever trying, to use a Ford valve, on a Mopar automobile.
That's uncharted territory.