The 'Impala' badge was first used for 1958 on a special version of the Chevrolet Bel Air, sold as a Sport Coupe and as a convertible. The first main stream Impala was the 1959-60 model built on the same GM A-body as the cheaper Buicks, Oldsmobiles and Pontiacs. The 1959 Impala had large flattened wings and tear drop rear lights but looked much more conventional for 1960. For 1961 the Impala was produced on the new GM B-body, and a new 'Super Sport' (or SS) option was offered which became a fixture in the Impala range. There were annual restyles until the 1965 GM B-body was given to the fourth generation Impala and it topped a million sales in one year. The fifth generation Impala became the largest ever Chevrolet and retained its sales. Growing changes in the market, fuelled by new Federal regulations over safety and emmissions caused the sixth generation Impala to be launched for 1977 on a 5-inch shorter platform.