What year is my Fuel System?

[Del72Chevy]

My truck is a 72 but I strongly believe that my fuel setup is not of a 72 truck. My in cab tank is not EEC there is no neck vent into the tank. My sending unit only has one port which goes strait to my fuel pump. Now it gets tricky because my fuel pump has three ports. The inlet from the tank, the outlet to the carb, and one other goofy looking outlet that goes back into the cab to the pillar u-tube vent. No charcoal canister anywhere just strait into the cab where the end is capped off. My tank cap is a regular one not vented but the seal is so old and dry rotted out it may be venting. I feel like I have an older than 72 tank with a 72 fuel pump with a vent line that is venting to nothing. Can I just cap this "vent" on the fuel pump and buy a vented cap for the tank? I want to put a new fuel pump on the engine and the edelbrock one only has two ports anyway so what would I do about the vent that goes nowhere?

Thanks Brian

[Del72Chevy]

I think I posted this in the wrong area can the moderator move it to engine? Thanks