I had my tank re-lined only to have it to spring a leak the following year. Not wanting to go through the expense of keep putting more Band-Aids on a 45 year old tank I settle on replacing it with a new one. I bought this Fuel Tank complete with sending unit off eBay.
According to very respectable source the early year production model have a different tank. What all the difference between early vs later, other than the filler neck and sending unit area, I haven't nailed down as of yet. My old tank was 12 gallon and this one is 16 gallon. This tank should be a direct replacement on later year production run Falcon's.
Some of the main differences, other than having more capacity, the tank height is around two inches taller, also the filler inlet hole was on the other side. Mine was on the left center and the new tank was on right center. This also will throw the vent tube on the wrong side.
The sending unit is sitting lower from the trunk floor so now the sending unit wire was too short to reach the unit. This in turn puts the fuel outlet lower also. The fuel filler tube that came with the kit was too big along with the cork gasket. I bought the correct size tube and gasket material at a local parts store.
I had to cut another hole in the trunk mat for the filler tube. I really hated to cut the mat because it is only five years old and it's the rubber mat, not vinyl. Instead of modifying the hard vent tube I added a new longer rubber hose.