Frankies son of course.
Bob Ellis - married to Darlene. He recently told me that he drove Frank's car once.
I also could speculate Karl Freyer.
My brother, Joe Inglin Jr., drove Franks Weld car several times.
One long shot. I think my father told a story once of George Unfried in one of Franks cars. I am clear that Frank drove George's cars on several occasions.
Final Jeopardy. Have to imagine that Bunny drove a Frank machine at least once.