 As a direct response to the 1973 oil crisis, the first automobiles to undergo downsizing in the interest of increased fuel efficiency were the full-size GM B-body and C-body platforms (used by all divisions except GMC).Used by the Buick LeSabre/Electra, Chevrolet Impala/Caprice, Cadillacs, Oldsmobile 88/98, and Pontiac Catalina/Bonneville, the B and C-bodies were among the best-selling car platforms in North America at the time.On average, from 1976 to 1977, engineers shed an average of 12 inches of body length and 750-800 pounds in curb weight (with some vehicles losing over 1,000 pounds of curb weight).