Valve question

Your already questioning wether the donor car one is the same that's on your car now.

That's good that your comparing the parts before you tear into everything.

When i first viewed your picture, the first thing that came to mind was, i never have seen an A body disc brake prop. valve that looked like that before.

That's why i dug the photo out of my computers files, of some past disc brake set up's that i have sold in the past, on and off eBay, and found lots of photos of prop valves and the lines.

Guess it's going to be your decision to install the one that you removed from the donor car.

Possibly some others might respond to your posting, with their thoughts between drum and disc valves, what they look like.

Anyway, happy wrenching, when installation day comes around with all your parts.