Hi everyone! I was looking through the Birds Nest catalog and came across a rubber piece, part 18912A, that was said to be for the antenna cable. Pretty much a disc of rubber with a hole in the center. My antenna cable comes out of the large opening toward the back of the inner fender and goes through the firewall along with some other wires via the firewall grommet shown in the catalog as part 359451S. Who knows how and where the Birds Nest part 18912A would go?
Thunderbird Registry #35780