Movie of the Week: Riverside International Raceway 1957

Today’s film is a color 8mm gem, and this one has something I need your help with. First, let me give you the heads up that someone uploaded the video with classical music, so if you’re not a fan of Bach or Beethoven, you might wanna turn the volume off. This obviously Riverside Raceway according to the description, and by the era of the cars and the parades, I’m guessing this was shot sometime around the opening weekend in September 1957. I always thought of Riverside as a sports car circuit, but we’ve obviously got Sprint cars running on dirt in this film. What gives? Anyone recognize the event? And check out the car show at 19:49 near the end of the movie!