When 18 dirt Champ Cars took the green flag at the California State Fairgrounds in Sacramento in 1970 and arced through the first turn in long, graceful power-slides, it marked the end of an Indycar era that predated the first Indy 500 in 1911. Never again would Indy cars run on dirt in a race that counted toward the national championship.
“It was the car owners’ idea. They didn’t want to spend the money on the different cars,” says Al Unser. “It didn’t make any difference to me what kind of car I was driving. A race car is a race car. The cars I liked most were the cars I could win in.”
According to this standard, Unser liked almost all of the cars he drove that year. Belted into a front-engined dirt car or a rear-engined pavement chassis, Unser won 10 of 18 races on superspeedways, short ovals, road courses and mile-long fairground tracks. The next year he won five more races, including Indy for the second year running. But this time around, every race on the schedule was run on a paved oval. The paradigm shift away from dirt was complete.