A couple of options both using an external EFI pump. External pumps work best with flooded suction.

First option is get a sump kit from Summit or Jegs and weld it into your stock tank and use the original pick up tube for your return.

Option 2 would be a fuel cell in the trunk.

I used option #2 on my 66 New Yorker because the original tank was rough and a fuel cell was cheaper than a new replacement and it solved the return line dilemma.

Kevin