What proportioning valve is this?

[Creedmoor]

My 68 Barracuda came with the brake parts to do a front disc swap when I bought it. Everything was pulled from a 67 Formula S. I’m trying to figure out the proportioning valve stuff. Attached is a picture of what came with the 67 stuff. Is the prop valve the smaller boxy thing? What is the roundish cylindrical thing? Thanks. I WILL have more questions as I move forward on this. I also need to see if the calipers are rebuildable.

 

[Professor Fate]

Actually, those look like '66 and earlier parts for the single pot master cylinder (which wasn't used in '67 and later). The distribution block is on the right, and the inline proportioning valve is on the left. I *believe* the small inline fitting is a residual valve, used in the rear line for the drums, since a single pot disc master wouldn't have one built in.
The distribution block in those early years only has four ports; one in from the master, one to each front wheel, and one to the rear (with the prop valve).
Very similar (if not the same) as the Mustang units from those years, which also used the K/H discs.

'67 and later systems with the dual-pot master cylinder used an all-in-one distribution/proportioning valve that looked more like this:

 

[Professor Fate]

In theory, you could keep your '68 drum brake distribution block and simply add the early prop valve to the rear brake line where it exits your block.
RockAuto currently has rebuild parts for your calipers, as well as complete reman units in stock.

 

[mvh]

1967 with disks still had a separate, adjustable proportioning valve in the rear line, located down by the frame rail. They went to the all-in-one non-adjustable unit later... I'm thinking 1970-up.

 

[mvh]

"Adjustable" should be in quotes. I wouldn't even try tweaking that thing after 60 years...

 

[Professor Fate]

1967 with disks still had a separate, adjustable proportioning valve in the rear line, located down by the frame rail. They went to the all-in-one non-adjustable unit later... I'm thinking 1970-up.

I still think that's a '66 and earlier distribution block, unless I'm just not seeing it right and it has 5 ports. '67 definitely had a dual master, which would call for a 5 port block.

 

[mvh]

I think you are right about that, yes. Definitely had a 5-port block.

 

[Creedmoor]

Prof.,

Thanks! That would explain the mystery single reservoir master included with all the parts I got. I also got a rebuilt Napa dual reservoir master. But, I think it’s for a full drum setup as both reservoirs are the same size. Pics below.

So, are you saying that, theoretically, I could use the ‘66 roundish cylinder proportioning valve I have (pictured in original post) after my existing drum/drum distribution block for the rears?

 

[mvh]

That's a drum/drum MC all right.