The cam is only indirectly a part of the vacuum system. Vacuum is created by the the intake sucking air into the engine. The cam only opens the valves. If the cam is not opening the valves enough to create vacuum, you have bigger problems. Check the hose and the one way valve to the brake booster.
Changing over is not as easy as it seems. You may need different brake pedals, shorter brake actuator shaft, possibly different brake lines and other assorted odds and ends. Usually easier to fix the problem than change it out.
That being said, the pedal feel afterwards should be just a little stiffer.