1973 Fuel Tank Seal

[KodaKing]

I recently bought a 1973 Mach 1 Clone. It's about 85% restored and was once a racer. It has new paint, tires, wheels, carpet, upholstery, and a rebuilt 302. I have just gotten it back from the shop where I had the wiring replaced. Nothing had worked but headlights, taillights, and wipers.

Here's my latest issue. The racer had a fuel cell in the trunk, and the original tank was removed from underneath. When it was restored, the cell was taken out and a new tank slung underneath. Where the filler neck enters the tank, there is supposed to be a seal/gasket that prevents spillage and fumes. It's not there. I've looked all over the internet, and other people have looked too. I asked at the 2 Ford dealerships here and was told that, "Yes, it's what you need, but we cannot get it!!" Is there anyone who knows where to find OR MAKE this seal, I would REALLY appreciate the info. I need to make this roadtrip drivable by May 21!!