GM No longer makes this seldom used pump but its available .. check the outlets.. it's the one pictured.

Its found on the  326 LeMans and the 400 GTO .. mainly with AC but who knows now half the time the pumps have been changed over the years as have engines etc.. but the main this is .. it has the return air vent pipe and a block threaded fitting...

May also be used on 67 full size or  Firebirds for the same specs, but note it has the 3 pipes......has the air pipe going back to the tank...  and the outbound to carby  pipe connects to a block rather then the typical threaded nut...

3 Pipes:

1 Vapor (Small pipe)

1 pipe from tank to FP

1 pipe from FP to Carby

Image is correct.