Fuel Line connection to fuel pump
 

I have a 1972 GMC 3500 Super Custom pickup truck that once had and extra fuel tank and now has 1 fuel tank. See photos - both lines from the sending unit run directly to the fuel pump. The larger fuel line (3/8") connects to the IN port of the fuel pump and the smaller fuel line (1/4") connects to the P port. Note - the tank selector lines are disconnected and the tank that sits behind the bench seat is the only tank in the truck.

Do I have the correct installation for the fuel lines to the fuel pump? There doesn't seem to be any other way.

Thanks for any help!

Re: Fuel Line connection to fuel pump
 

IIRC the smaller, 1/4", line is fuel return

Re: Fuel Line connection to fuel pump
 

OK - so then it looks correct? Is there any venting needed?

Re: Fuel Line connection to fuel pump
 

I assume your cap is vented

I have a 2nd line on my 72 C10, it goes to EVAP canister

Re: Fuel Line connection to fuel pump
 

I'll double check - thanks!

Re: Fuel Line connection to fuel pump
 

I believe my cap is vented

Re: Fuel Line connection to fuel pump
 

there should be no rubber connections in the cab on the liquid line

Re: Fuel Line connection to fuel pump
 

Isn't factory lines inside cab use short soft fuel line to bridge between fuel sender lines in tank to hard lines coming up through cab from PS frame rail??

Re: Fuel Line connection to fuel pump
 

Factory was a hard line up through the floor to a flared fitting. Vapor line had a small rubber connection

Re: Fuel Line connection to fuel pump
 

I was under the impression that 71 and older had flared fitting and no return . If I remember correctly I replaced the rubber lines on my 72 when I did the seat and there were two . Both my 68s are single line . Can’t get a pick of my 72 as the seat is in and no tracks to move it but my 68 Golden has only one line and is I believe original to the truck

Re: Fuel Line connection to fuel pump
 

Correct.
My '71 has a delivery line, suction line, and return line, --- 3 lines on the pump. The tank is vented through a line in the upper passenger side of the tank. The line runs to the canister mounted below the battery tray. The vent line connection at the tank is a rubber line, while the 2 lines at the tank are flared hard line connectors.

Re: Fuel Line connection to fuel pump
 

FWIW my 72 has soft line connection both fuel and vapor lines at the top, PS, behind seat bridging to the hard lines from tank and the ones that come up through floorboard to window height then bend and go toward the gas tank.

IDK if this is "stock"...way truck came when I bought it. Tank has been replaced by PO