Jim Hickman was fatally injured in a practice crash for the Tony Bettenhausen 200 at Milwaukee, he was 39 years old.

[1] After the F1 Grand Prix on Saturday, the track would be converted to an oval for an Indy car race on Sunday.

This was cancelled after FISA rescheduled the Grand Prix for September and instituted a rule that banned two open-wheel series with engines over two liters from competing at the same venue on the same weekend.

[3] O  Oval/Speedway R  Dedicated road course *The Stroh's 200 was scheduled for April 25, but postponed a week due to rain.

Mario Andretti was credited with winning the pole position for the Michigan 500, although he started 33rd due to a pre-race practice accident.