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 formule 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 anything goes. As long as the car had two seats and bodywork enclosing the wheels, and met basic safety standards, it was legal. 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 hillclimb 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 went over to race against them occasionally).
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 was 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 1000 horsepower (750 kW) (some teams claimed 1,500 hp (1,100 kW) in qualifying trim), wings, active downforce generation, very light weight 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 dominating 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 lacklustre 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 in this. F5000's reign lasted for only two years, with a second generation of Can-Am following. This was a fundamentally different series based initially on converted Formula 5000 cars with closed-wheel bodies. There was also a 2L class based on Formula Two chassis. The second incarnation 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 the time, the spectacular cars and the lineup of talented drivers. Can-Am cars remain popular in historic racing.