Just a word of caution for anyone intending to do this conversion. Back in the early 1950's my father had a 49 Oldsmobile he used as a test bed for various modifications, including power brakes. He fitted a Hydrovac that was intended for a 3/4 ton pickup to it, and ended up with a brake system that required a feather-light touch on the brake pedal or it would lock up all the brakes. In those days before seat belts, I can remember getting bounced off the dash pretty often. Use a Hydrovac unit that's matched to the weight of the vehicle you're driving and/or the load you're planning to haul.
Jerry
