Can-Am started out as a race series for Group 7 sports racers with two races in Canada (Can) and four races in the United States of America (Am). The series was initially sponsored by Johnson Wax. The series was governed by rules called out under the FIA group 7 category with unrestricted engine capacity and few other technical restrictions.
The group 7 category was essentially a Formula Libre for sports cars; the regulations were minimal and permitted unlimited engine sizes (and allowed turbocharging and supercharging), virtually unrestricted aerodynamics, and were as close as any major international racing series ever got to have an "anything goes" policy. As long as the car had two seats, bodywork enclosing the wheels, and met basic safety standards, it was allowed. Group 7 had arisen as a category for non-homologated sports car "specials" in Europe and, for a while in the 1960s, group 7 racing was popular in the United Kingdom as well as a class in hill climb racing in Europe. Group 7 cars were designed more for short-distance sprints than for endurance racing. Some group 7 cars were also built in Japan by Nissan and Toyota, but these did not compete outside their homeland (though some of the Can-Am competitors occasionally went over to race against them).
SCCA sports car racing was becoming more popular with European constructors and drivers, and the United States Road Racing Championship for large-capacity sports racers eventually gave rise to the group 7 Can-Am series. There were good prize and appearance money and plenty of trade backing; the series was lucrative for its competitors but resulted, by its end, in truly outrageous cars with well over 1,000 horsepower (750 kW) (the Porsche team claimed 1,500 hp (1,100 kW) for its 917/30 in qualifying trim), wings, active downforce generation, very lightweight and unheard of speeds. Similar group 7 cars ran in the European Interserie series, but this was much lower-key than the Can-Am.
On-track, the series was initially dominated by Lola, followed by a period in which it became known as the "Bruce and Denny show", the works McLaren team dominated until the Porsche 917 was perfected and became almost unbeatable. After Porsche's withdrawal, Shadow dominated the last season before Can-Am faded away to be replaced by Formula 5000. Racing was rarely close—one marque was usually dominant—but the noise and spectacle of the cars made the series highly popular.
The energy crisis and the increased cost of competing in Can-Am meant that the series folded after the relatively lackluster 1974 season; the single-seater Formula 5000 series became the leading road-racing series in North America and many of the Can-Am drivers and teams continued to race there. F5000's reign lasted for only two years, with the second generation of Can-Am following. This was a fundamentally different series based initially on converted F5000 cars with closed-wheel bodies. There was also a two-liter class based on Formula Two chassis. The second iteration of Can-Am faded away as IMSA and CART racing became more popular in the early 1980s but remained active until 1987.
Can-Am remains a well-remembered form of racing due to its popularity at one time, the spectacular cars and the lineup of talented drivers. Can-Am cars remain popular in historic racing.