The ACO was working closer with IMSA and Bill France Jr. of NASCAR and Daytona Speedway, to encourage inter-series racing. To that end four IMSA and two NASCAR-spec cars were entered. Although the race clashed with a NASCAR race at Riverside two of the junior teams arrived. Hershel McGriff raced with his son in their Dodge Charger, while Dick Brooks shared his Ford Torino with Dick Hutcherson (also a NASCAR-driver, and veteran from the 1966 race with Ford) and Marcel Mignot (a driving instructor at Le Mans circuit). The cars had to be adapted for hard right-hand turns and be fitted with window wipers and lights. Easily the heaviest cars at the race, they attracted considerable media attention and were very popular with the French public. Current American Trans-Am champion John Greenwood had previously brought Corvettes over to race. This year his IMSA-spec modified Corvette, nicknamed the “Batmobile” arrived. The chassis was designed by Bob Riley (ex-Ford GT and Saturn rocket engineer) and aerodynamics by Zora Arkus-Duntov. Although heavy, and with big disc-brakes, its giant 427 cubic inch V8 pushed out 700 bhp and got the car up to an impressive 355 kp/h (220 mph). Michael Keyser bought one of the new Chevrolet Monzas modified by DeKon Engineering, built to take on Porsche in the IMSA series. Tom Vaugh and Diego Febles also entered two of those IMSA-spec Porsches for the race.