Sports racers were growing in popularity by the mid-1960s. The Group 7 sports racers were the Big Boys. They had very few technical restrictions. No homologation requirements. Engine capacity was unrestricted. Forced induction was allowed. No aerodynamic restrictions, for all intents and purposes. It was essentially a free-for-all. Group Seven became the foundation for the SCCA Can-Am series, inaugurated in 1966. The series was named Can-Am because of it's two races in Canada and four races in the United States of America. The series was very popular, and drew large prize money, which only fueled its popularity over the years. By 1973, the series produced some of the most irrational cars motorsports has ever seen.
In many ways, the Chaparral 2E was the first step in that direction.
Chaparral - another name for a road runner - was formed by former Formula One driver Hap Sharp and Texas-born engineer Jim Hall in 1962. The original Chaparral race cars were built by Troutman and Barnes. Jim Hall had purchased two of them to race. They started with heavy modifications to those cars. When Hall and Sharp realized they needed to build their own cars, they asked and received permission to continue using the Chaparral name. From that day forward, all of the Hall/Sharp cars were referred to as Chaparral 2 models.
The early Chaparrals were designed to compete in the United States Road Racing Championship (USRRC) series. Hall had strong factory support from General Motors, including engineering and technical support in developing an automatic transmission for his cars.
Jim Hall changed the automotive paradigm of aerodynamics with the 2E. Based on the 2C aluminum chassis, the 2E was loaded with never before seen innovation. He moved the radiators from the nose to ducted pods on both sides of the cockpit. The area of the nose typically used for those radiators was then repurposed to create a Venturi tunnel, creating extra downforce. And of course there was the trademark feature of the 2E - the large, high mounted adjustable rear wing. The 2C was actually Hall's first model that utilized an operator adjustable rear spoiler. The use of the automatic transmission allowed the driver's left foot to be free to operate a pedal that adjusted the aero mechanism. In the high-winged 2E, Hall claims that at 17 to 18°, the wing generates 240 pounds of downforce at 100 mph. The angle can be flattened to 4 or 5° for straights.
Initially the movable rear wing, which pressed down directly on the rear suspension uprights, caused a downforce imbalance when a driver flattened it on a straightaway. Hall rectified this by incorporating an aluminum flap that closed off the Venturi tunnel when the wing was flattened. When the brakes were deployed, the flap opened and the wing returned to its most aggressive angle.
Aside from the automatic transmission and aero advances, the 450 hp aluminum 327ci small block Chevy-powered 2E was otherwise fairly typical.
The 2E did not win the 1966 Can-Am series championship, but not for lack of speed. It didn't even attend the first race. The team was in Europe campaigning it's 2D closed-coupe sports car at the time. The 2E also suffered some reliability issues, but when it wasn't breaking it was brutally quick. The drivers Phil Hill and Jim Hall managed fourth and fifth respectively in the points, with one victory.
Jim Hall has stated this is his favorite car. So much so that in 2005, he created continuation models of the 2E car from the original drawings and molds. This is the car that had some pretty serious influence on so many of the race cars we love and watch to this day.