ACL Chaparral 2E

The mid-engined Chaparrals, built from 1963 through 1970, are among the most iconic sports-racing cars ever built, up there with vehicles such as the Ford GT40, Ferrari 330P4, and Porsche 917. The cars are significant for a number of reasons. First, they were cutting edge. Chaparral founder Jim Hall pioneered aerodynamic developments such as wings and ground effects, as well as alternative forms of construction.

Hall's small operation out of Midland, Texas, was also one of the most successful American competitors in international motorsports, taking on and beating the established sports-car makers from Europe. For example, in 1964 and '65, Chaparral won 11 of 16 races in the SCCA's U.S. Road Racing Championship, the precursor to the SCCA Canadian-American Challenge (or Can-Am) series. The Chaparral 2 and 2C also won 11 other major races in that period, including the 1965 12 Hours of Sebring.

The 2E was brilliantly conceived. The wing was mounted high to get the cleanest airflow possible and set at a 17-to-18-degree angle to generate 240 pounds of rear downforce at 100 mph. According to Hall, that angle could be flattened to four or five degrees, depending on the racetrack.

The radiators and the oil tank were repositioned at the back of the car to get as much weight as possible over the tail. Hall: 'That was all done probably because we were Texans. We wanted to eliminate heat (by moving the radiator from in front of the driver), and that gave us the freedom to do what we wanted aerodynamically at the front. And we also wanted better traction.' The air that would have flowed into the radiator at the nose was used as a venturi tunnel to create additional downforce.