About how much vacuum s needed for a power brake bosster to work well? I ahve 10-11 inches of manifold vacuum and a hard pedal that gives me moderate stopping power. If I idle for 5-10 minutes the brake work better, but for only a couple of times. :confused:

ive been told from a very reputable company master power brakes that you need a minimum of 17 inches of vac for good power ....try their website www.mpbrakes.com...or (http://www.mpbrakes.com...or) you can call them,i just purchase power brakes for my 69 and thats what they told me...good luck....