What kinda cam you running that it doesn't pull enough vacuum for the brakes? You can get an electric vacuum pump (IIRC, some 80's model Buicks and the like had them) and keep your power brakes, if that's something that might interest you? Not sure if it's a possibility with our power steering systems, but you could also look into doing the hydraboost that the later model Cobras had, as another option.