Teri Garr has an uncredited role as a waitress. When she met François Truffaut on the set of Close Encounters of the Third Kind (1977), she was stunned to discover that he had seen this film, recognized her from it, and remembered every detail of the movie (he was a great admirer of Howard Hawks).
The magazine Mike Marsh (James Caan) is reading before the Atlanta 500 is the January 1965 issue of Road & Track Magazine.
The white #28, 1964 and 1965 Ford Galaxies featured were owned and prepared by Holman and Moody. These cars were driven by Fred Lorenzen in NASCAR competition for eight wins in 1964, and four wins in 1965.
Holly Farms' Ford in the movie driven by Ned Arp.was in fact driven by Junior Johnson who was in the inaugural class of the Nascar Hall of Fame. In fact, Junior Johnson was the first driver to have a non-car or car parts related sponsor which of course was Holly Farms Chicken from the early 60s to his retirement from driving in 1966.