Skip,
Don't see why the transmission would get in the way. If anyting, the auto tranny might be a problem, but the manuals are usually OK.
My 1958 1 ton dually came with a hydrovac (or is it hydra vac... I'm not sure). Anyway it's the one that connects to the intake manifold vacuum. It works with the single cylinder brake master cylindre. They were an option on the 1 tons, and I think they might have been stock on the heavy spring dually.
My truck is not currently functional, so I can't tell you if it works well or not, but I suspect it's better than without!
By the way, have you rebuilt your brakes? Have you adjusted them? My brake wheel cylinders were shot, and I have installed 4 new. I'm in the process of new hoses throughout. Then on to the master cylinder and the hydrovac.
I'm contemplating if it wouldn't be cheaper to buy a new dual cylinder master cylinder with booster built in. I think it will be cheaper than rebuilding the old master cylinder and hydrovac, and it will certainly be cheaper, and safer. I've seen ones claim that they "bolt right in" to the old mount and connect to the old pedal. Just not sure yet.
