In Pixar's Cars, The King's race car is painted with the number 43.
The King is a veteran Piston Cup racer and one of the film's most respected competitors. His blue race car carries number 43, a visual tribute to real NASCAR driver Richard Petty, who famously raced with that number. Richard Petty also provides The King's voice in the English version of the film.
The number helps distinguish The King from the other major racers. Lightning McQueen uses 95, while Chick Hicks uses 86. Doc Hudson's historical racing identity is associated with 51, but he is no longer an active competitor when the main story begins. These numbers are recurring visual clues throughout the racing scenes.
The King represents experience and sportsmanship. He is nearing the end of his racing career, and the final race raises the question of whether the championship should pass to a younger driver. His treatment of Lightning and Chick helps establish the difference between racing success and personal character.