bad brake booster on 68/C10?

[Steve Beecher]

Hi Guy's..

I suspect my 68/C10/350ci w/ power brakes has a problem with the brake booster. Here's what happens'..sometimes when i apply the brakes hard not only does it seem like there isn't much stopping power, the engine will start running rough after i let off and get back on the accelerator pedal. I've checked for vacuum leaks arond the carb, etc. and nothing was found. I tested the booster the only way i know by removing the booster line to the booster from the intake manifold after shutting the engine off and letting it set for a couple minutes..it seems to holds vacuum?..This problem is driving me nuts!! I've come here before and y'all have been most helpfull.....thanks!

Steve