grommet for this hole in the firewall

[dmjlambert]

Hi, where do I find a grommet for this hole? This is a 7/8 inch hole and the cable passing through it is about 1/4 inch, it is for the cold/hot blend door control cable. 1969 cab with A/C.

I have been able to find 7/8 grommets with a large center hole, but would rather find one with no hole so I can drill, or with a small center hole so I can hug that control cable that goes through it.

I wonder if the factory just put a square of that gooey black tar-like tape on the hole.

Firewall grommet kits do not have a grommet for this hole (or for any 7/8 hole)