As it turned out, demand for cars was strong, and the feared immediate postwar recession didn't happen. So Ford Motor Company and Chrysler Corporation did not market redesigned cars until the 1949 model year.
It was slightly different for industry leader General Motors. New A and B bodies did not appear until 1949. Affected brands were Chevrolet, Pontiac and Buick. Ditto for Oldsmobile's 70 and 80 series cars. But a redesigned top-of-the-line C body was released for Cadillacs and Oldsmobile 98s. It also was used for an extended 1949 model year for Buick's Super and Roadmaster lines.
This post deals with 1948 Oldsmobile 98s that had those new C bodies.