Sunday 5th June 1966
A. J. Foyt crashed in flames during practice for the Rex Mays 100 Mile Race at Milwaukee, ending his supreme reign of the USAC championship trail of recent years. Heir apparent Mario Andretti (Dean, Brawner-Hawk/Ford 65) seized the opportunity to snatch the win from Roger McCluskey (Hopkins, Eagle/Ford Mk 2) and Joe Leonard (AAR, Eagle/Ford Mk 2), with the supercharged Gerhardt/Drake-Offenhauser of Art Pollard (GCR) fourth and Chuck Hulse (Leader Cards, Watson/Ford 65) and Al Unser (Mecom, Lola/Ford T90) fifth and sixth, respectively.