Chevrolet Impala Convertible
The Impala remained Chevrolet's top-selling model with the fifth generation. A high-performance big block V8 was still available in the form of the Turbo-Jet 454, which produced 365 hp in 1971, but power decreased as the years went along. The 1971 redesigned B-body would be the largest car ever offered by Chevrolet. The hardtop Sport Coupe continued to be offered; it was a smoothly sloped semi-fastback reminiscent of the 1961 "bubbletop" styling. A three-speed manual transmission remained standard at the beginning of the year, but in the spring of 1971 all V8-equipped full-size GM cars got Turbo Hydra-Matic as standard equipment. Interestingly, Powerglide remained optionally available for six-cylinder cars until the 1973 models.
Source: Wikipedia, 2012