I am looking to buy a rebuilt smog pump for my 1967 390 SanJose car. However, I am aware of two versions of this pump, one with two rubber hose fittings and another with three. I believe I need the pump with two fittings but I am not sure. The '67 Ford shop manual doesn't give me a good picture of the setup so I need some help. Can anyone shed some light on this for me?