for endurance racing in 1966. It won at 1000 km Nürburgring in 1966 with Phil Hill and Joakim Bonnier driving. It also competed in the 1966 24 Hours of Le Mans, withdrawing after 111 laps. The Chaparral 2D was equipped with a 327 cubic-inch displacement (5.3-liter) aluminum alloy Chevrolet engine producing 420 horsepower; the car weighed only 924 kg. The 2E was based on the Chevrolet-designed aluminum 2C chassis and presented Hall's most advanced aerodynamic theories to the racing world in 1966. The 2E established the paradigm for virtually all racing cars built since. It was startling in appearance, with its radiators moved from the traditional location in the nose to two ducted pods on either side of the cockpit and a large pivoting variable-incidence wing-mounted several feet above the rear of the car on struts. As opposed to an aircraft wing, it generated downforce instead of lift and was attached directly to the rear suspension uprights, loading the tires for extra adhesion while cornering. A ducted nose channeled air from the front of the car upwards, creating extra downforce as well. By depressing a floor pedal that was in the position of the clutch in other cars, Hall was able to feather or flatten out, the "normally" negative-incidence wing's angle when downforce was not needed (as on a straight track section) to reduce drag and increase top speed. An interconnected air dam also closed off the nose ducting for streamlining. When the pedal was released, the front ducting and wing returned to full downforce position. Until they were banned, many race cars, including some in Formula One, had wings on tall struts. The resulting accidents from their failures led to pivoting wings mounted on the suspension prior to being fully banned. The 2E scored only one win, at the 1966 Laguna Seca Raceway Can-Am with Hill driving. Hall stuck to an aluminum 5.3-liter Chevrolet engine in his lightweight racer while the other teams were using 6- to 7-liter iron engines, trading weight for power. The 2E was a crowd favorite and remains Hall's favorite car. In the 2F Hall applied the aerodynamic advances of the aluminum 2E to the older fiberglass chassis closed-cockpit 2D for the 1967 racing season. A movable wing mounted on struts loaded the rear suspension while an air dam kept the front end planted. The radiators were moved to positions next to the cockpit. An