The Buick Motor Company was formed in 1903, it was General Motors' upmarket car, second only to Cadillac. The Grand Sport was introduced in 1965 as a performance option package on the Skylark. In 1968, the GS became a separate series and only available in 2 door Hardtop or Convertible. In 1970, the 400 was replaced by the 455. Base engine was still the 315hp 350, then the 350hp 455 (hood scoops), the high performance 360hp 455 Stage 1 version got a more aggressive camshaft, higher compression and 4 bbl carby. The GSX was an ornamentation package, Saturn Yellow or Apollo White (Rallye wheels, spoilers, stripes, suspension) Also available in 1970, the Riviera 2 door Hardtop, base and GS In 1970, the 112 and 116 inch wheelbase base model Special was dropped leaving the upscale Skylark and Skylark Custom, 260, 285 or 315hp 350 cu in V8s, in 2 door Hardtop or 2 and 4 door Sedan. The 123 inch wheelbase LeSabre and LeSabre Custom, 260hp 350 or 350hp 455 cu in, was available in 4 door Sedan, 2 or 4 door Hardtop and Convertible.