Difference between gas tank return line vs vapor line?

[ScottH]

Can anyone shed some light on this? I have a 72 which had the original tank removed and relocated to under the bed. I would like to return it to the original location. I picked up a tank from a 72 parts truck which has the EEC lines on it. Can anyone tell me how the extra line connect - to the fuel pump as a return line or to a vapor cannister?

My truck is a 402 engine with the fuel pump with the return line but does not have a cannister. Should the return line located on the gas tank upper left hand corner be connected to the fuel pump return line?

Any info is greatly appreciated.

Thanks!