(Image of a 1968 Buick GS)
Buick sold nearly 16,000 Buick Skylark Gran Sports in 1965. The Gran Sport was an option on the Buick Skylark once again in 1966, and they had blacked out grilles, GS badges, and rear facing hood scoops that were non functional. There was a higher horsepower version of the 401, rated at 340 horsepower. Sales dipped a little due to the higher cost of this model compared to other muscle cars, and the new muscle car models being offered by other manufacturers.
Buick GS Becomes Its Own Model
Buick made the Gran Sport its own model in 1967, naming it the Buick GS. This was the beginning of a long life for probably the biggest and most powerful muscle car from Buick. The 1967 Buick GS had a new engine, which actually produced exactly 400 ci, but was a newer design, compared to the dated "Nail Head Engines" of the previous Gran Sport lines. The new engine ran smoother and had higher revolutions also. Buick also introduced a smaller engine, the 340. The models were named the "GS 340" or the "GS 400", of course depending on what engine was used. Sales were similar to the 1966 Gran Sport model, and didn't reach the previous high of the 1965 Gran Sport model year.
Buick GS Stage 1
With sales not increasing with the new GS model line, and other manufacturers showcasing some serious power in their muscle cars, Buick went all out on the 1968 model and made some drastic structural changes. They cut 3 inches off the wheelbase, and 4.4 inches overall on the length of the GS. The smaller engine was bumped up to 350 ci, and there was an exclusive California model only sold in California. This model had the 350 engine, and came with special badges, trim, a 2 speed automatic, vinyl top, and the Deluxe steering wheel.
There was a rare dealer installed option that would define the future of this model, called the "Stage 1 Special Package". This was installed only on the 400, and it came with a better cam, better compression at 11.0:1, stronger valve springs, and a better transmission. Officially, Buick labeled the Stage 1 Special Package as adding about 5 bhp to the specs, but it more likely brought the horsepower rating to a staggering 390 bhp.
1969 brought the Stage 1 and Stage 2 packages, adding 345 and 360 bhp respectively. The hood scoops also became functional this model year, adding even more power to the mighty Buick.
Lifting the Corporate Ban
GM lifted its corporate ban of not allowing an engine larger than 400 ci in an intermediate body, and Buick took full advantage of this by dropping in a 455 ci engine. Working hood scoops, more displacement, a hotter cam, and bigger valves added up to a lot of power, but if that wasn't enough (of course it's never enough), you could add the Stage 1 Package to the model. This turned the 1970 Buick GS into a truly scary model. 510 ft-lb of torque is truly amazing, and when you consider that it achieves it at only 2800 RPM, you have to take a bow to this beast.
New trim packages were also unveiled in 1970, called the GSX. In 1970, the only GSX color options were Saturn Yellow or Apollo White ( I detect a NASA theme here!), and included front and rear spoilers, body stripes, larger tires, hood tachometer, and better suspension. The California GS was dropped in 1970.
1970 seems to be the height of the Buick GS. GM policies, increased government regulations, and higher insurance premiums and gasoline prices were taking a toll on all manufacturers. The GSX trim continued on in 1971, but there were many more color options. The change of engine design to use low lead gasoline cut the power ratings of the engines, and 1972 was the last model year of the Buick GS. It would continue on in 1973 as a package on the Buick Century, 1974 on the Apollo model, and finally ended in 1975 back on the Century model.