Hi Chad ! Nice build so far!!!
In response to your PM, Here are some pictures of my hydro boost set up.
I wish we could attach pictures in a PM, so I will have to just attach them here in your thread.
The linkage- I made an adjustable push rod using 3/8" rod couplings and 3/8" threaded rod. I cut off the shaft from the hydro boost and left just a short stub. Drilled out one side of a 3/8" rod coupling to the same diameter of the shaft, pressed it together and spot welded in place. I had converted the existing eye that fit on my 64's brake lever previously in the same way.
Then use the all-thread to fit between the two rod couplings and use 3/8"nuts and lock washers as jam nuts when the adjustment is perfect.
It would be better if one side was left handed thread so you could adjust like a turn buckle, but this works OK. The hydro boost side spins so I just left a little free-play and movement of the pedal arm before engagement and tightened the jam nuts.
The hoses- I grabbed the hoses from the 94 Astro van as they are metric and use O-rings. Cut off the hose right next to the old pressed on connection.
NAPA has some 3/8" compression fittings that they pressed on new 3000 PSI hoses. I had one side of each hose made, took them home and test fit and marked each hose for exact length, took them back to NAPA and them them cut to the mark and the other end pressed on. The compression fitting are rotatable before you tighten them as the hose is very stiff. I cut the hose from the old flared fittings and reused the flared ends on the power steering pump and gearbox side . I used bulk transmission hose to make up the return lines and Tee'd back in to the pump return port.
The mount -- I had already purchased the mount from CaptainFab and had installed power brakes , but was not pleased with the vacuum booster I installed .
I may have had a bad booster but I also have a cam in my inline 6 and the heads are shaved so the 15" of vacuum at idle was not enough to have the braking results I was after,
I mounted the 94 Astro van hydro boost and master on the CaptainFab bracket and reconnected the brake lines.
Remember that on the master cylinder that the larger rear plastic tank connects to the front discs and the front smaller tank connects to the rear drums.
The proportioning valve is off a 71 C-10 and a modified S-10 bracket.
It stops AMAZING now!!! Maybe a little touchy, but it will not slide the tires on dry roads. It just stops fast and will set you into the set belts!!
Oh yeah--- get some new shoulder harness belts, these are too much brakes for the old style lap belts!!