Buick Gran Sport (GS)

The Buick GS, like many other GM intermediate muscle cars, began life as an option on an existing model in 1965. It would become one of the most formidable muscle cars of all time, despite the fact that it came from a company not known for performance.


Buick Skylark Gran Sport, 1965

Buick was inspired by the popularity of the 1964 Pontiac GTO to create their own muscle vehicle. Buick simply shoehorned their existing 401 cubic inches full-size car engine into their Skylark to create the Buick Skylark Gran Sport. General Motors set a corporate maximum of 400 cubic inches for intermediates, but Buick simply shoehorned their existing 401 cubic inch full-size car engine into their Skylark to create the Buick Skylark Gran Sport. This Buick engine, known as the “nailhead engine” because of the size of its valves, was introduced in the 1950s and was known as the Wildcat 445 (according to its torque rating). The hardtop, pillared coupe, and convertible Skylark Gran Sports all received the convertible’s beefed-up frame and unique suspension. The model was an instant hit, with nearly 16,000 units sold in 1965. For a first attempt, it’s not terrible.

Buick Skylark Gran Sport, 1966

For its second season, the 1966 Buick Skylark Gran Sport received additional power and fresh looks. Gran Sports had blacked-out grilles, GS badging, nonfunctional rear-facing hood scoops, and simulated front fender vents, while Skylarks had new rear sloping sail panels that stretched the rear roofline past the back window. The ancient 401 engine was brought back to produce 325bhp, although there was also a 340bhp version. This engine shaved 1 second and 1/2 second off the 0-60- and 1/4-mile times, respectively. Despite these enhancements, the Buick’s greater price relative to other GM intermediates resulted in a significant decline in production, with only 13,816 being built.

Buick GS 400, 1967

Buick replaced its old 401 cubic inch engine with a fresh new 400 cubic inch engine, as well as a new designation, the GS 400, for 1967. The new engine produced the same 340 horsepower as the top 401 engine, but it was more modern in design, ran better, revved higher, and had a futuristic air cleaner. The hood scoops were now facing forward, although they were still non-functional. A new three-speed automatic was launched, and many testers preferred it to the three- and four-speed manuals. In 1967, the “junior” GS was introduced, nicknamed the GS 340 after its 340 cubic inch engine. It wasn’t bad, although it was frequently overshadowed by its bigger sibling.
340 horsepower at 5,000 rpm and 440 pound-feet of torque at 3,200 rpm.


Buick GS 1968

In 1968, the Buick GS received a major structural redesign, shedding 3 inches of wheelbase and 4.4 inches of overall length. The huge rear-end design and sail creases down the sides contributed to the overall weight gain. The powertrain of the junior GS was increased to 350 cubic inches, but the 400 cubic inch unit remained the same. The California GS was released as a new model. This model was essentially a GS350 with special “California” badges and trim, a standard two-speed automatic transmission, a vinyl top, chrome exterior trim and wheels, and the Deluxe steering wheel. It was sold solely in California. In 1968, a dealer-installed option was available that included a hotter cam, 11.0:1 compression, stronger valve springs, and a redesigned transmission for the 400 cid engine. Officially rated at 345bhp, a modest 5 bhp more than the original 400 cid engine, experts say it was closer to 390bhp, and it shaved a second or more off 1/4-mile times. It was known as the “Stage 1 Special Package,” and it foreshadowed big things to come.


Buick GS 400, 1969

The Buick GS finally gained standard functional hood scoops for cold-air induction to fend off increased competition. Buick claimed that this enhanced horsepower by 8% and torque by 6% over the rpm range but did not affect the engine ratings. The 350 cid engine continued to power the GS350 and California GS, but the big news for 1969 was the inclusion of two Stage 1 and Stage 2 options for the 400 engines. The Stage 1 version increased output to 345bhp, while the Stage 2 version increased output to 360bhp.

Buick GS 455, 1970

The best Buick GS of all time debuted in 1970. Buick responded by fitting a whole new 455 cubic inch engine into its restyled GS when GM eventually relaxed its corporate rule on engines larger than 400 cubic inches in intermediate bodies. The 455 had higher displacement, larger valves, and a hotter cam than the 400, as well as standard cold air induction via operable hood scoops. The 455’s had a 350-horsepower engine and a stump-pulling 510 lb.-ft of torque. Except for Cadillac’s 472 and 500 cid V-8s, this was the highest torque rating of any production engine, and no engine reached it at a lower rpm (2800rpm). A Stage 1 package added a hotter cam, wider valves, and a redesigned carburetor as if that wasn’t enough. Buick claimed 360 horsepower, but most testers believed it was closer to 400. On top of that, Buick debuted the GSX look package. The GSX package included front and rear spoilers, contrasting body stripes, meaty tires, a hood tach, and a heavy-duty suspension. It was only available in Saturn Yellow or Apollo White. All of this combined to create the ultimate Buick muscle vehicle. The GS350 was also offered, but the California GS was discontinued. The 350 V8 gained a huge boost in power, now producing 315 bhp and 410 lb-ft of torque. For a little block, it’s not awful.


Buick GS 1971

1971 marked the formal start of the end of the muscle car era. Under pressure from rising government restrictions, insurance premiums, and gasoline prices, GM mandated that all of its engines run on low-lead gasoline, resulting in lower compression ratios and lower power ratings. The 350-engine lost 55 bhp to 260 horsepower, while the 455 and 455 Stage 1 engines lost 35 bhp and 15 bhp, respectively, to 315 bhp and 345 bhp. The new GSX trim kit came in a variety of colors, including red and black.


Buick GS 1972

Due to ongoing government limitations and a shrinking muscle car market, 1972 would be the final year for the GS to be built on the Skylark platform. Government laws now mandated that engines be rated “net” with all accessories installed. Although the engine output remained same from 1971, the power ratings were drastically reduced. The regular 350 was reduced to 195 horsepower, while the 455 and 455 Stage 1 were reduced to 225 and 270 horsepower, respectively. The GSX was still available, and the normal ram air induction piece had been altered from two square induction pieces to one square and one triangular induction piece.

Buick GS 1973

The GS flag was carried on by a GS option on the 112-inch wheelbase Buick Century coupe after the Skylark-based GS was discontinued. The only manual gearbox option in the Buick lineup for 1973, it was differentiated by inconspicuous decals, blacked-out headlight surrounds and grille, fat wheels and tires, and the only manual transmission choice in the Buick lineup. Gran Sport engine options began with a two-barrel 350 CID V8 producing only 150 horsepower (net), but the 225 bhp (net) 455 CID V8 option, which was available on any Century coupe, became more fascinating. The 270 horsepower (net) Stage 1 455, which included camshaft, carburation, and air filter improvements and came standard with a Posi-Traction restricted slip rear end, was only available on the Gran Sport. Few cars were faster in 1973 than a Stage 1 455 Buick GS, demonstrating how far performance had plummeted by that point. In 1973, just 728 Stage 1 GSs were sold.


Buick GS 1974

In 1974, the GS name was transferred to the Apollo platform. The once-dominant 455 V8 was retired. A Rallye steering wheel, a modified suspension, power front disc brakes, styled wheels with trim rings, sport mirrors, a stripe package, and body side molding were still available as part of the GSX package. A two-barrel 350 V8 rated at 165 horsepower, or a four-barrel variant rated at 175 bhp were available. There were 1,562 GSXs made in all.


Buick GS 1975

In 1975, the GS name returned to the Century platform, although it was only a shell of its former brilliance. Buick performance would not be seen again until the turbo-charged Buicks of the mid 1980s when true Buick GS manufacture halted in 1972.