†- During time trials, Bill Vukovich II turned his first lap at 185.797 mph (299.011 km/h), to set the one-lap track record, and was the first driver to officially break the 180 mph (290 km/h) barrier. He, however, crashed on his second lap, and did not complete the four-lap qualifying run. Later in the afternoon, Joe Leonard qualified a four-lap average of 185.223 mph (298.088 km/h) to break the four-lap 180 mph (290 km/h) barrier. Later in the day, however, Bobby Unser qualified even faster, over 190 mph (310 km/h), and became the first pole position winner to break 180 mph (290 km/h) and 190 mph (310 km/h) for his four-lap average.