Buick GSX

Buick GSX at a glance

The GSX was the top version of the Buick Gran Sport; this page covers the package in detail, while the Gran Sport article tells the story of the whole GS line from 1965 to 1975.

Buick's late entry in 1970

Buick showed a GSX prototype at the Chicago Motor Show in February 1970 to test buyers' reaction. Production began in March and ended in May 1970. Wikipedia describes the GSX as Buick's answer to the Pontiac GTO Judge, the Oldsmobile 4-4-2 W-30 and the Chevrolet Chevelle SS, and Street Muscle adds that it was meant to bring more customers into Buick showrooms. The car did not appear in the 1970 standard catalogue; a four-page leaflet described it instead.

The GSX was never a separate model: it was an option package ordered on top of a Gran Sport 455, and it added a substantial amount to the price of the car.

What the GSX package included

According to Street Muscle and Wikipedia, every GSX had:

• a full-length black body stripe (with red pinstripes, per Wikipedia's 1971–1972 description), a blacked-out bonnet area and GSX badges;
• a black front spoiler and a rear spoiler;
• a tachometer mounted on the bonnet;
• black bucket seats, a floor shifter and sports mirrors;
• chrome-plated 15 × 7-inch Rallye wheels with G60-15 tyres;
• a 1-inch front anti-roll bar and a rear anti-roll bar, stiffer springs (450 lb/in front, 144 lb/in rear), a quick-ratio steering box, upgraded bushings and heavy-duty rear lower control arms;
• 11-inch vented front disc brakes with power assistance and, on Stage 1 cars, 9.5-inch rear drums.

Wikipedia adds a limited-slip differential and Buick's four-link rear suspension. The Muncie four-speed came with Hurst linkage; the Stage 1 cars were offered with a Turbo Hydra-Matic 400 with a special torque converter, and either gearbox could be ordered with either engine. In 1970 buyers took 199 four-speeds and 479 automatics.

455 and 455 Stage 1 compared

All figures except power, torque and the 1970 split are from Street Muscle; the ratings and production split are from Wikipedia. The Stage 1 heads had smaller combustion chambers for higher compression. Wikipedia also cites a claim that the weakest of 15 Stage 1 engines tested produced about 317 kW (425 hp), but marks it as unverified.

How fast was the GSX?

Motor Trend tested a Gran Sport Stage 1 coupé weighing 1,728 kg (3,810 lb) in 1970 and recorded a quarter mile of 13.38 seconds at 105.5 mph, according to Wikipedia. Street Muscle attributes the same test result, plus 0–60 mph in 5.8 seconds, to the GSX Stage 1 and says automatic cars were only slightly slower.

Colours and production

In 1970 the GSX was painted either Saturn Yellow or Apollo White, both with a black interior. The two sources reverse the split: Wikipedia gives 187 Saturn Yellow and 491 Apollo White, while Street Muscle gives 491 Saturn Yellow and 187 Apollo White.

For 1971 and 1972 Buick widened the colour and trim choice and, according to Wikipedia, lowered compression after 1970. The production figures for those years include the 350 four-barrel, the standard 455 and the Stage 1. The sources give no net ratings for the 1971–1972 GSX.

Buying a Buick GSX

• Year and colour: a 1970 GSX must be Saturn Yellow or Apollo White with a black interior; other colours point to 1971 or 1972, or to a clone.
• Engine: in 1970 every GSX had a 455; a 350 is correct only for 1971–1972 cars.
• Package parts: bonnet tachometer, both spoilers, the stripe and the chrome Rallye wheels should all be present.
• Stage 1 details: the 3.64:1 axle (3.42:1 with air conditioning) and the Stage 1 camshaft and heads.
• Numbers: with 846 built, documents matter more than badges.

Photo gallery

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