Last night I went on a test drive with the new power booster & MC, and was anxious because the motor only makes about 10" of vacuum at idle. I've always been told that 14-15" is the absolute minimum for power boosters.

Even with a little bit of air in the system, the brakes work great! Even after several pumps of the pedal at idle, it feels very good. It doesn't have as much assist as it would with more vacuum, but frankly, I don't like a soft pedal. This is with a 1.125" MC, stock booster, stock front discs and 11" drums in back.

Just thought this might be helpful to those who need to know.

Thanks Matt!

My motor makes 13" roughly at idle, and I run the factory booster. I have never had any issues whatsoever. Even after repeated braking, like while coasting downhill, it still works fine, it does firm up a bit however.

Stock Z/28 only makes 9"-10" of vacuum at idle, and they built thousands of them, all with power brakes. :thumbsup:

Stock Z/28 only makes 9"-10" of vacuum at idle, and they built thousands of them, all with power brakes. :thumbsup:

That was my philosophy...