KELSEY HAYES PROPORTIONING VALVE KIT SOURCE

Yeah, I don't think that's the same unit. The K-H part we are talking about was used 67 (and maybe earlier) to 72. It's the adjustable proportioning valve that only came with the 4-pot disc brakes. Not used 73-76.
Well, suit yourself.
Tried to help, with my reply.
All that i can tell you is, others have bought that "kit" used it, and didn't have any difficulties with it.
That's how i saved the link, in my computers files.
There have been many, numerous threads about your issue, in the past, so maybe do a search and see what comes up.

No such thing as an "adjustable" proportioning valve on any of the A body line of cars, so i haven't got a clue what your talking about.

If you do have a 71, and then the "factory" valve will be this one.
And this valve was used from 70-76 on the A body line of cars.
And i had lots of them in the past, that i used to put up for sale, on this site.
So i think i know about these valves.

Prop Valve A Body 003 (Small).JPG

UCAs 001 (Small).JPG