Brake Booster Question

Demonic said
It is inches of Mercury - "Hg. Not pressure, negative vacuum. But we knew what you mean. :D

What sort of brakes? Kelsey-Hayes w/ a dual diaphragm booster? Drums? Your vacuum should never go to zero. Any pics?

I used a donor 1974 Dart and its a factory front disc car with rear drum. The booster is a 9" booster.

I don't have pics.