Program from 1964 CRA 'Big Car' race
I found a 16-page program (PDF download here) from the Sept. 5, 1964, California Racing Association "Big Car" race at Hanford Speedway on eBay and while most of the program is light on good stuff, it does contain one gem: an article that finally sheds light on the first events and races at the track.
The "History of the Track" article said Marchbanks Stadium, as it was then called, opened with rodeo events in February 1950 and quarter-horse racing on a half-mile track with a quarter-mile straightaway. The first auto races followed "on about May 10, 1951," when jalopies hit the track.
From 1950 to the September 1964 race, events at the track included "hardtops vs. jalopies, stock car racing, sprint cars, midgets, and event boat racing on a small lake built in the center of the stadium. At one time bull fights could be enjoyed here."
According to the article, 20,000 people jammed the track on July 4, 1961, to watch the Blue Angels perform overhead as part of an air show at the nearby Lemoore Naval Air Station.
The article said the track was renamed Hanford Speedway "a few weeks ago," in conjunction with the new ownership group involving Kal Simon, Tommy Francis and others. It also mentioned a 1955 NASCAR Magazine article on Marchbanks Stadium, so that's something I'll try to trace down.
As for the September 1964 CRA race, Hal Minyard picked up his ninth win of the season in a long 100-lap event that drew at least 44 entries. Hanford hosted a second 100-mile CRA Big Car race a month later, on Oct. 11. Minyard won that race too.