installing all new part for factory air conditioning. the dash control has three vacuum ports . i have one line going to the blenddoor, one to the heater core supply, one to the fresh air vent on the passenger side & one from the intake manifold. does anyone know what hose goes where? do i need a vacuum canister in this also? ports are labled 1,2,3. i believe that 69-72 are the same . thanks mike