The USAC championships are three different classes and thats a fact. Maybe you could say it was a little extra special to win all in one year, But the fact remains the same. The SIX are the only ones to win all three divisions.
Sooo, a horse wins 3 races on a similar track in one season. A driver runs 6 different kinds of cars, in a total of maybe 70 to 80 races in a season, and we are comparing the two just because they have the same name? You could also count winning the 3 dirt miles a triple crown or pick 3 midget or sprint races and call that the triple crown. How many guys have won in all 3 divisions in a single season? That could be a triple crown. Just sayin
NHRA ( National Horse Racing Association ) says the name needs changed due to the fact that it's to similar to the name they use. Kinda like Mid / Mud Summer Classic. LOL.