Johnny Mantz was a Hollywood stuntman who raced stock cars, midgets, sprint cars and Indy Cars. He frequently won but didn't win many championships as the money was in winning races not series.
Johnny Mantz died 48 years ago, he was 54
The only American-born driver to win the Formula One World Drivers' Championship (Mario Andretti, an Italian American driver, won the World Drivers' Championship in 1978, but was not born in the United States). He also scored three wins at each of the 24 Hours of Le Mans and 12 Hours of Sebring sports car races.