The Impala name was first used for the full-sized 1956 General Motors Motorama show car that bore Corvette-like design cues, especially the grille. Painted emerald green metallic, with a white interior, the Impala concept car featured hardtop styling. Clare MacKichan's design team, along with designers from Pontiac, started to establish basic packaging and dimensions for their shared 1958 General Motors "A" body in June. The first styling sketch that would directly influence the finished Chevrolet automobile was seen by General Motors Styling vice president Harley Earl in October. Seven months later, the basic design was developed. The Impala was introduced for the 1958 model year as top of the line Bel Air hardtops and convertibles. From the windshield pillar rearward, the 1958 Bel Air Impala differed structurally from the lower-priced Chevrolet models. Hardtops had a slightly shorter greenhouse and longer rear deck. The wheelbase of the Impala was longer than the lower priced models, although the overall length was identical. Interiors held a two-spoke steering wheel and color-keyed door panels with brushed aluminum trim. No other series included a convertible. The Impala was restyled on the GM B platform for the first time for 1961. The new body styling was more trim and boxy than the 1958–1960 models. Sport Coupe models featured a "bubbleback" roof line style for 1961, and a unique model, the 2-door pillared sedan, was available for 1961 only. It was rarely ordered. A "Super Sport" (SS) option debuted for 1961. This was also the last year the top station wagon model would have the Nomad name. Power brakes were $43.