The film marked a deliberate strategic shift for AIP. The studio had been moving away from its beach party formula, which was losing commercial appeal, and toward youth rebellion pictures. AIP executive Deke Heyward characterised the new direction as moral tales exploring young people's protest against the establishment. Stock car racing had previously appeared in the 1965 AIP film Red Line 7000; Fireball 500 was specifically conceived to address the subject from a teenage perspective.
Director William Asher had made five beach party films with Avalon and Funicello and co-wrote this film with Leo Townsend, who had worked on three of those earlier productions. Fabian signed a multi-picture deal with AIP in late 1965, and Fireball 500 was the first film he completed under that arrangement. Principal photography began on 9 March 1966.
Stock car racer Dave "Fireball" Owens travels from California to Spartanburg, South Carolina, to compete against the local champion Sonny Leander Fox. After Owens beats Leander in a race, he attracts the attention of Leander's girlfriend Jane Harris and a wealthy woman named Martha Brian. Martha persuades Owens to drive in cross-country night races without informing him that he is actually smuggling moonshine; her partner Charlie Bigg manages the operation.
Leander, who runs his own still and smuggling ring separately, challenges Owens to a dangerous Figure 8 race that ends in a draw. After a fellow driver, Joey, is killed during a run, Owens and Leander investigate together and discover the crash was caused by a large mirror placed across the road; Charlie Bigg was responsible, motivated by jealousy over Owens's relationship with Martha. IRS agents had earlier threatened Owens with imprisonment if he did not assist in dismantling the moonshine ring. Owens wins the climactic race while Leander is severely burned.
The title vehicle — the "Fireball 500" — was a 1966 Plymouth Barracuda heavily customised by car designer George Barris, powered by a 273 cubic inch V-8 engine producing 275 hp. In the film it is jokingly referred to as the Batmobile; Barris had also built the Batmobile for the Batman television series, which premiered in January 1966.
Footage from the production, specifically a shot of the car designated "4B" (belonging to the character Jim Douglas) rolling onto its roof, was later reused in the demolition derby sequences at the opening of the 1968 Disney film The Love Bug. The film is notable for its depiction of Figure 8 racing, regarded as one of the more hazardous formats in stock car competition.
Critical reception was mixed. Variety praised the "snappy pace" and the attempt to add dramatic substance to the teen-film formula, while Bosley Crowther of The New York Times dismissed it. The film served as a transitional point for its leads: it was the first film Funicello made after the birth of her daughter, and the first of Fabian's multi-picture deal with AIP.
A follow-up announced in July 1966 as Malibu 500 was eventually produced as Thunder Alley (1967), again featuring Fabian and Funicello. Fireball 500 helped seed a cycle of racing pictures that included Track of Thunder (1967), Hell on Wheels (1967), and The Wild Racers (1968).