Buick Gran Sport History
1965 - Buick was a year late coming to the 'Muscle Car' party. Buick's 401cid engine was used but dubbed a '400' due to GM's policy of a maximum of 400 cid for mid-size A-body cars. The Gran Sport was based on the mid-size Skylark body.
1966 - Buick continued with the 401 cid nailhead engine for 1966.
1967 - The Gran Sport was now it's own series of Skylark-based models. A new design 400 cid engine was used and the line was now called the GS 400. A GS 340 and GS California model was introduced for sale in California only and not nationally advertised by Buick. The car was little more than the Skylark hardtop with new trim and badging.
1968 - The GS California and GS 350 replaced the same models as in 1967 but with Buick's 349 cid engine. The GS 400 was offered in both the convertible and hardtop body styles. Buick's Super Turbine 400 transmission (more commonly known as simply the TH400) was introduced
1969 - The GS 400 remained basically the same for 1969 with the updated body changes.
1970 - The 400 cid engine was replaced with Buick's 455 cid engine for 1970. The Stage 1 option upped the horsepower from the base 350 hp to 360 hp and 510 lb. ft. of torque. It's reported that Buick Engine development engineers pulled several production-line engines and dyno tested them and the lowest horsepower tested was 376 hp.
A stage 2 option (first developed in 1969) included a different camshaft, headers, intake manifold, high compression forged pistons, hollow pushrods, and some calibration changes to the ignition and carburetor. The 1970 Stage 2 had round exhaust port heads, matching Kustom brand headers, a radical camshaft, Edelbrock B4B aluminum intake, Holley #4781 carburetor flowing 850cfm - basically a GSX clone.
The 1970 GSX was available in two colors, Saturn Yellow and Apollo White. Bold body-length striping, mostly black hood, hood-mounted tachometer, rear spoiler, and black front spoiler.
1971 and 1972 - The GSX package became an option on and Gran Sport. Only 124 were ordered in 1972 and 44 in 1972.
Rivera GS
The Rivera GS is a high-performance version of the Buick Rivera and was produced from 1965 through 1975. The 1965 model was called Rivera Gran Sport and showed Gran Sport badging while later models showed GS badging. The 1965 (and optional for 1966) was powered by the 425 cid "Super Wildcat" engine with dual 4-barrel carburetors and dual snorkel chrome air cleaner assembly.
1965
1970
