Fuel line question

Evening folks,
Working on a '72 Duster, swapping out the /6 for a 318. My plan is to put in new fuel line. What the '72 had was two lines; fuel and return? The YearOne catalog and web site only lists one line. What have y'all done? In the engine bay they ended in very different places, one ended at the K-frame while the other snaked it's way along the inner fender and firewall.
Thanks,
C

Duster 4-28-2008 026.jpg