1971 Buick GS 455
1971 Buick GS 455. Click image to enlarge

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Article and photo by Bill Vance

Buick bills itself as a producer of “Premium American Motorcars,” and its target audience is the somewhat conservative, fairly affluent buyer. But in spite of this rather traditional approach, Buick has occasionally broken out of that mould to market some surprising high performance machines.

In 1936, for example, it introduced the Century, named for its 100 mph (161 km/h) capability. It was basically Buick’s light Special model fitted with the Roadmaster’s 5.2-litre (320 cu in.), 120 horsepower overhead valve, straight-eight engine.

In the 1960s, the Buick Wildcat wrapped sybaritic luxury in a sparkling performer, and Car Life magazine dubbed it the “Executive Hot-Rod.”

Then in the 1980s came the Buick Grand National, and outrageous GNX. They were powered by Buick’s 3.8-litre (231 cu in.) turbocharged V6, and the Grand National could, in its peak 235
horsepower form, sprint to 96 km/h (60 mph) in under five seconds (Car and Driver 4/86).

There was another Buick name that was associated with higher performance: Gran Sport, or GS. The Gran Sport and GS nomenclature were available as a sportier option on several Buicks from 1965 to 1975, including the Riviera, Wildcat and Century. But arguably the most famous and best remembered of the GSs (there was also a GSX), were the Skylark-based models.

The Special/Skylark was Buick’s entry in the intermediate market segment in the 1960s, with the Skylark being the upscale version. The Skylark’s Gran Sport option became available in 1965, and its main claim to fame was a 325-horsepower, 6.6-litre (401 cu. in.) V8 rather than the regular 3.7-litre (225 cu. in.) V6, or 4.9-litre (300 cu. in.) V8.

It remained the Skylark Gran Sport for 1966, and then in 1967 became just the Buick GS. The GS 340 got a 260 horsepower, 5.6-litre (340 cu. in.) V8, while the more potent GS 400 had a 340
horsepower 6.6-litre (400 cu. in.) V8.

This new 6.6-litre engine (there was also a 7.0-litre (430 cu in.) version), was a replacement for the Buick “vertical valve” V8 that had arrived in 1953. The new one eliminated the breathing restrictions imposed by the vertical valve layout.

General Motors intermediates, including Buicks, were restyled for 1968, and the side sculpting on the Buick intermediates, including the GS, echoed the look of full size Buicks. The two-door’s wheelbase was reduced from 1967’s 2,921 mm (115 in.) to 2,845 mm (112 in.) for 1968. The GS 340 became the GS 350, now with 5.7 litres (349 cu in.) and 280 horsepower, while the GS 400 remained.

Car Life magazine called the 1968 GS 400 the most luxurious of the muscle cars, which included the Pontiac GTO, Oldsmobile 4-4-2, Chevelle SS 396, Ford Torino, Dodge R/T and Plymouth Road Runner. But in spite of this, they said it “… takes a back seat to none in performance.”

To back this up they tested a GS 400 with a dealer-installed “Stage 1 Special Package.” This included a special camshaft and higher compression pistons, which allegedly raised horsepower to 345, although Car Life smelled a rat. Based on its performance, they thought it was more like 50 extra horsepower, not five. With this package the GS 400 sprinted to 96 km/h (60 mph) in 6.1
seconds. Its low 3.91:1 rear axle limited top speed to 177 km/h (110 mph).

The GS went into 1969 little changed, although the quarter windows were eliminated in favour of flow-through ventilation. The performance package became a factory option.

For 1970 the GS was restyled, and the GS 400 became the GS 455, with the 6.6-litre bored out to give 7.4 litres (455 cu in.), which upped horsepower by 10 to 350.

There was also a factory Stage 1 performance package, and with this 360 horsepower option fitted, Car Life (12/69) recorded a zero to 96 km/h (60 mph) time of 6.5 seconds. This wasn’t as fast as they got with the ’68 GS 400, but the ’70 was tested in much hotter weather and had a higher 3.64:1 axle. At 208 km/h (129.5 mph) its top speed was 31 km/h (19.5 mph) higher.

Also available was a GSX version, which emphasized better handling. The GSX included stiffer suspension, bigger tires and wheels, front disc brakes and a four-speed manual transmission.

This would mark the peak of the muscle car era. Emission controls were sapping horsepower, and in 1971 the industry reduced compression ratios to accommodate the lower octane low-lead or no-lead gasolines that were being phased in. The major emission control device, the catalytic converter, couldn’t tolerate lead.

The impact of emission control hardware and lower compression was significant. The 1970 7.4-litre GS, with a 10.0:1 compression ratio, was rated at 350 horsepower, but this dropped to 315 horsepower with the 1971 8.5:1 compression.

The combination of brutal insurance premiums, lower power and performance due to emissions restrictions, and rising safety concerns, spelled the end of muscle cars in the early 1970s. There
would be a 1972 Skylark-based GS, but that would be the last. A GS package was offered on the Century until 1975, and GSX on the 1974 Apollo, but the magic was gone.

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