 Complete the following phrase:  By 1959, the doubleheader and tripleheader formats had been mostly abandoned in favor of one longer feature. In addition, support races were filling the docket to improve the show for fans. The event moved to the Indiana State Fairgrounds oval in 1972-1973 and was held as two 50-lap features. But the 1973 Night Before the 500 was plagued by rain, much like the 