In 1972 Unser set another Indianapolis 500 record for the fastest qualifying time at 195.94 miles per hour. In 1974, he won his second USAC National Driving Championship and a year later he won his second Indianapolis 500 in a race that was rain-shortened on lap 174. From 1979 to 1981 Unser raced in the CART series for Team Penske winning ten races. In 1980 he became the first driver to win the California 500 four times. His career ended in 1981 following a controversial win at Indianapolis.