72 Demon fuel fill vent tube ideas?

I was just going to drill a 5/16" hole up high on my fuel neck and weld in a short 1" long piece of 5/16 fuel line so I can slide a rubber hose over it to make the bend to go back to hard pipe and down through the filler neck floor grommet out to the ground. Problem is that the fuel neck on my 72 demon gets installed from the outside in and just fits through the hole in the quarter. So anything I try and weld to the neck will not allow me to then install the neck? Plus I want to be able to remove it as well if I need to pull it back out. Anybody got a good way to accomplish this? What if I just bought and used a vented gas cap? Will that do the same thing?? Or do I need to have this vent. Nothing running up front either.