Having not seen a video on how to insert the filler tube, I made one! This is good for not only Mavericks and Comets, but Mustangs from 1971 and later.
Mine has a Mustang tank in it. The tank apparently has a tube coming up out of it. There is a large diameter rubber hose that is clamped to the tube. I changed my filler tube because it did not 'clock' correctly with the gas cap (emblem was not level). I bought a maverick filler tube to replace it. Fortunately, it was clocked correctly, but I had to cut 1.5" off the tube so it would fit. Never know what you'll find....