i would suggest
if you absolutely need to drive it , get under there with some chevy wire and pull the TP (kickdown) arm almost all the way back and tie it there. at least you will be getting higher line pressure.
also , like these guys are saying, plug the vacuum port where the booster line runs to on the intake and see how your engine runs. i bet it runs good. power brakes without a booster working do work, but it can be dangerous