The source of this footage, John McClure, was a member of the San Diego Jr. Chamber of Commerce and sports car fan and driver. His position with the Chamber put him in a position to combine his passions as part of the team that developed the Torrey Pines Race Course. Thankfully, John also carried a camera around with him for races up and down the West Coast.
This footage is from the inaugural race at Riverside International Motor Raceway on September 21-22, 1957. Lot's of fantastic racing machines here — Ferrari, Maserati, Porsche, home built specials, Jaguar... You name it.
More vintage racing at thechicaneblog.com
Update: Commenters on the Chicane and elsewhere have pointed out that this video also contains footage from the November 16-17 1957 SCCA Nationals race in Palm Springs.