1972 McLaren M16A Race Car, Driven by David "Salt" Walther

As automobile racing speeds increased, repurposed dirt horse tracks became inadequate. In the 1910s promoters turned to wooden boards, which provided a smooth road surface and were less expensive than bricks or concrete. But rotting wood required frequent replacement. Improvements in concrete and asphalt made board tracks obsolete in the 1930s. The 1.25-mile board track at Altoona, Pennsylvania, operated from 1923-1931.

This is Henry Ford's first race car. After his first auto company failed, Ford turned to racing to restore his reputation. He raced "Sweepstakes" against Alexander Winton on October 10, 1901, and, to everyone's surprise, the novice Ford beat the established Winton. The victory and resulting publicity encouraged financiers to back Ford's second firm.

Scotsman Jim Clark won the Indianapolis 500 with this rear-engine car in 1965. After his victory, a traditional front-engine car never won that race again. The Lotus-Ford combined a European Formula One-inspired lightweight chassis with a big Ford V-8 engine. The Lotus-Ford's success effectively killed the traditional Indy roadster and established a new design for American race cars.