Amazing early photograph acquired as-is - believed to show Ralph De Palma, Eddie Pullen and Roscoe Sarle. An amazing user on Reddit identified the likely year and history below:

Based on the clues in the notation and in the photo itself, this appears to be from Heat Race 1 of the April 10, 1921 races at the Los Angeles Motor Speedway, also referred to as the Beverly Hills Speedway or the Beverly Hills Board Track, an ambitious but short-lived (1920-1924) high-banked 1.25 mile wooden oval track in Beverly Hills, California.

DePalma (in the white #4 Ballot) won that 20 lap/25 mile heat over Roscoe Sarles by a reported 0.02 seconds at a 106.3 MPH average (if ChampCarStats is to be believed), an amazingly close finish. Pullen would finish 5th of the 8 cars in the heat, which also featured Joe Thomas, Tommy Milton, Eddie Hearne, Alton Soules, and Jimmy Murphy. There were 3 more 20 lap heat races and then a 40 lap main event on April 10, 1921, with Murphy taking the main event.