Joe Leonard is the "Only Racer in the World" to have won multiple National Championships in both automobile and motorcycle racing back to back. Leonard raced in the USAC Championship Car series in the 1964-1974 seasons, with 98 career starts, including the 1965-1973 Indianapolis 500, sitting on the pole in 1968 in the Granatelli turbine car. He finished in the top ten 60 times.
He is seen standing with Al Unser in a previous post. Link HERE