I came up with a pretty good replacement for the almost impossible to find rubber fuel filler grommet for the W100 tw and tp's.
It is a lower shift boot from a 1987-93 Mustang GT, with some minor modifications. I trimmed the flange off and opened up the center hole to 2 inches. I was fortunate enough to have the remenants of the original fuel grommet and glued the center to the new shift boot.
I got this one from Fox Mustang restoration.. http://www.foxrestro.com