Yeah when I got it back the brakes were ok, but not optimal so I called him and he said it takes 20 inHg to operate it efficiently and I had 14-15 so I opted to use a vacuum canister and hide it. How much vacuum do you have? Have a cam?
I did not measure the vacuum but will post it this weekend. I assume the cam is the original that came in the slant six. The booster worked great before I had the hard pedal problem, I figured the booster finally gave up after 46 years.