OK, so this won't affect the "easy" answer, but I think it strange to use "NASCAR" as the clue for A.J. Foyt. Although he did compete in a limited way in NASCAR and with some success, he is much more renowned for his Indycar and sportscar racing career.
I suppose they were "known by their initials" as the quiz title suggests, but they wouldn't fit in with the others. I don't know that anyone called them F.D. Roosevelt or J.F. Kennedy.