The cars didn't run most of the time, so they had to be pushed down hills in order to get them to move. Moreover, the cameras used to film the cars were undercranked in order to perpetuate the illusion that they were moving faster.
Both Sylvester Stallone and David Carradine did much of their own driving. In addition, producer Roger Corman drove in scenes that were shot on public streets, since the custom-built cars used in the movie were not street legal and the film's stunt drivers did not want to be caught driving them by the police.
Several of the cars in the movie are re-bodied Volkswagens, including a VW Karmann-Ghia (Matilda's Buzz Bomb). The white Resistance Army car that chases Frankenstein very briefly before crashing and blowing up is a 1965 or 1966 Ford Mustang. Nero's car was based on a Fiat 850 Spider, and Frankenstein's on a Chevrolet Corvette.
The film retains only the basic premises of the original short story by Ib Melchior; the characters and incidents are all different. The story focuses on just one mechanic and driver, and one anti-racer. In particular, it does not include the President or the special driver Frankenstein.
Roger Corman wrote the original treatment of the film, which was serious in tone, but thought it was not right and, in his words, was "kind of vile". He decided the dark material of the story would be better served by making the movie into a comedy and had Robert Thom rewrite the treatment.
Mary Woronov, who plays Calamity Jane, did not know how to drive a car, so a stunt driver did all the actual driving for her in the movie. For close-ups, Woronov sat in a car towed behind a truck with a camera crew riding in it.
Explaining why he took the Frankenstein role, David Carradine says, "I started that picture two weeks after I walked off the Kung Fu (1972) set, and that was essentially my image, the 'Kung Fu' character, and a lot of people still believe I'm that guy. The idea actually was: No. 1, if you walk off a television series, you better do a movie right away or you might never get to do one. And the second thing was to do something right away that would create the image of a monster to get rid of the image of that little Chinese guy that I'd been playing for four years. And, you know, it did kick-start my movie career."
The car in which President Frankenstein and Annie drive away after their wedding is a Richard Oaks Nova kit-car, actually based on the Volkswagen Beetle chassis (but obviously not the body). These were available in kit form for many years starting in the mid-1970s.
Was theatrically re-released in France in the mid-80s with its title changed from the literal translation "La Course a la Mort de l'an 2000" to a more evasive "Les Seigneurs de la Route" (meaning "Lords of the Road"). This time, David Carradine and Sylvester Stallone shared the top billing on the posters.