My 1970 Charger 500 is almost done

[kent]

So you used your original mounting plate? And the booster was different. Too bad. Love it when they say simple bolt up. I have yet to install mine from Nat Moparts. They said a simple bolt up. Hope Scott is correct.

[darbgnik]

So you used your original mounting plate? And the booster was different. Too bad. Love it when they say simple bolt up. I have yet to install mine from Nat Moparts. They said a simple bolt up. Hope Scott is correct.

Yessir. Maybe it matches manual plates? But it certainly didn't match my original power drum stiffener plate. So the linkage opening had to be opened up, as well as new mounting holes drilled. I left the stiffener plate on the car for this, but it seemed like I was doing the same mods to the firewall, as the stiffener plate.

[b5blue]

Manual and boosted plates differ but what you have isn't a 70 B Body unit per-say. If it works it's all good right! 

[darbgnik]

Another little update.

After replacing everything brake related, save the rear drums themselves, and taking the car for a test drive, I soon discovered that the booster was only effective for the first brake application, then less so after that. So, out comes the vacuum gauge finally. I knew it would be low vacuum seeing as the car came with an old Mopar purple cam, but I was surprised to find it with 3 inches. Multiple timing movements left me with 7 inches....... still not ideal.

Phase 2 of brake upgrade commenced. I bought a GM branded Hella vacuum pump, the same one used on Cadillac CTS's and Volvo turbo cars, for their vacuum brake boosters. It's a modern, read quiet, rotary style pump, as opposed to the old noisy piston style pumps. I already had a relay box in the car, so I used the last available relay spot, the 6th, and wired in a vacuum switch made for brake vacuum pump actuation so that the vacuum pump was only on when needed. I then welded up a bracket to hang the rubber mounted pump under the battery tray out of sight. I put a check valve just before the vacuum pump, so the vacuum wouldn't leave the circuit, and installed a tee in the vacuum line from the manifold. Now it gets two separate feeds for vacuum, with a check valve at the pump and motor. So if the vacuum motor quits, it still gets the paltry motor vacuum. Conversely, if the engine dies, it will still have effective braking till the battery drains.

I must say, with the vacuum pump installed the brakes got downright touchy. In a good way. In a modern car way. Just touchy in comparison to how they'd always been in this car.

Parts list:
1 - ACDelco 20804130 GM Original Equipment Power Brake Booster Pump
2 - 3/8" aluminum check valves off of Amazon
10' - 3/8" fuel line(I bought vacuum line, but the fuel line was considerably thinner, thus better looking)
1 - 3/8" plastic vacuum tee
1 - vacuum switch similar to this one:    https://www.amazon.com/dp/B078T5NL4S/ref=twister_B07PKLX241?_encoding=UTF8&psc=1
8 -  small hose clamps

In the pics you can see the pump and bracket I made(just mocked up on the bench), a partial view of the pump, check valve, and pressure switch hidden under the battery tray, and the finished product, with the new vacuum line coming from under the battery tray, and teeing into the brake booster. Also in that pic is the relay box, with the relay for the vacuum pump now wired in.

[Kern Dog]

You write very well. It is obvious that you paid attention in school.   
The proportioning valve looks the same to me as the ones used in the Disc brake 1973-76 A body cars that served as brake donors for so many cars.
The drum-drum distribution blocks I've seen are about 2/3 the size and rectangular, not irregular in shape like yours. Some have called these prop valves the "Texas" valve for the shape sort of mimics the state in shape.

[darbgnik]

You write very well. It is obvious that you paid attention in school.   
The proportioning valve looks the same to me as the ones used in the Disc brake 1973-76 A body cars that served as brake donors for so many cars.
The drum-drum distribution blocks I've seen are about 2/3 the size and rectangular, not irregular in shape like yours. Some have called these prop valves the "Texas" valve for the shape sort of mimics the state in shape.

Yes, what I meant was that the brake lines installed in the same locations as the drum/drum, on this prop valve. It does look like the A body unit.