I have a 73 Swinger and am starting to reassemble, installing gas tank tonight - my 67 has a vent through the filler tube, this car shows a return line - are there options here and if it is best to run it - where does it terminate in the engine bay ? Car has been disassembled for many years. Is there a diagram out there that will show me routing of the line ? I see the return lines cost just as much as the feed lines - maybe I could find a used filler neck from an older car ?