Thinking about converting my 4 wheel drum brakes to front power disc brakes. How much vacuum pressure do I need to operate the power brake booster properly? I have a mild cam in the car now and am worried it will not have enough vacuum to effectively operate the power brake poster.

I have just gone through an extensive brake challenge and any thing over 12 will work just fine. Sometime as little as 9 will work.

Jimmy,
Thanks for the info. Did you convert from manual to disc and if so, which kit did you go with?
Bobby

No I didn't convert. I just had some brake problems and had to chase the whole system to find a couple of problems. The booster seemed to be the biggest problem

I used to have 7 at ildle ..nps...lets face it when do u use the brakes?
Engine braking...foot off throttle = high vac
Cruise = high vac
Sitting at lights, well if u take your foot off then put back on a few times sure, the pedel hardens up...to manual brakes...give the engine a plip and power brakes are back...Anyway, u are not moving so dont meed the power brakes..
The vac is trapped in the vac canister by a non return valve..takes a few pumps to use it up.