Vacuum problems

Does anybody knows or have a map of the Vacuum lines for a 1978 V8? I think I have vacuum leaks at the a/c doors or engine. When I push the pedal, the air in the front goes to def and heater, a couple of seconds after it returns, I think that the different doors open and closes when I rev the car and want to know why, I think is a bad vacuum line or I am missing something.