Rare Rides: The 1970 Buick GSX and GSX Stage 1

In our past installments of this column, we’ve had a look at some extremely precious offerings from most of the usual suspects. We’ve reviewed Chevys, Mopars, Pontiacs, Fords, and even an AMC.

These brands constituted the bulk of performance cars from the Golden Era of muscle. Therefore, they yielded the majority of the rarest ones. However, there are a smattering of scarce cars from unlikely marques that deserve our attention as well.

In that spirit, we’ll have a look at a vehicle from a company not widely known for muscle or performance cars. So, on that note, let’s get to it with the 1970 Buick GSX and GSX Stage 1!

It is not generally common knowledge that Buick is one of the oldest auto manufacturers in the world, and the single oldest American firm.

The 1970 Buick GSX Stage 1. (Photo courtesy of Mecum Auctions.)

A company with a rich history, which was later acquired by General Motors, Buick was immediately slotted in at the higher end of GM’s offerings, just beneath Cadillac.

As General Motors evolved and established the marques that we are familiar with, such as Pontiac, Oldsmobile and Chevrolet, Buick remained a high-tier brand, offering luxurious cars that were less expensive than Cadillacs.

Things were business as usual at Buick into the late-’60s. They were still building big, ponderous, luxury cars that appealed to an older, upper-middle-class demographic. But times were clearly changing, as the muscle car era was in full swing, and even their elderly clientele were itching for a bit more spice in their vehicles.

So it was, that the higher-ups at Buick decided to produce a car to compete with the likes of the high-powered Shelby and Boss Mustangs, SS Chevelles and Camaros, and Hemicudas and Hemi Challengers.

To get their beast into production quickly, plans to design a completely new car were nixed, and instead focus was aimed at modifying an existing car in their lineup. The car they chose was the Gran Sport, which happened to be based on the venerable A-Body Skylark.

A 1965 Buick Gran Sport. (Photo courtesy of Hemmings.com.)

The Buick Gran Sport was no slouch to start with. First introduced as an option package for the Skylark in 1965, it included stiffer suspension, a stronger rear axle, upgraded brakes, a front anti-roll bar, and dual exhaust.

The largest engine permitted by GM at the time in a mid-sized car, the “Nailhead” 400 V8, was installed. Actually displacing 401 cubic-inches, this lump was good for 325 horsepower and a prodigious 445 pound-feet of torque. Mated to it was a standard three-speed manual. Four-speed manual and automatics were optional. All of this yielded a car which could power through a quarter-mile in 16.6 seconds at 86 mph.

In 1967, Buick ditched the Nailhead in favor of an entirely new 400 cubic-inch V8 that produced 340 ponies to up the ante. A year later, Buick raised the bar again, making the Gran Sport. Rechristened as the GS, it was a standalone model with an extensive redesign.

A glorious, fully-restored 1970 GSX. (Photo courtesy of Mecum Auctions.)

For 1970, the target model year for their hardcore muscle car, Buick pulled out all the stops. A sheet-metal refresh of the entire A-Body line was performed, which extended to their new GS-based top dog – the GSX.

The front end of the GSX featured a deeply recessed and blacked-out, two-section grille ringed with brightwork and flanked by a pair of twin headlamps. The previous generation’s “sweepspear” side design element was ditched in favor of a single horizontal crease below the beltline.

A conventional straight bumper replaced the previous concave design, and the iconic Buick VentiPorts were finally laid to rest. A cold-air induction system on the hood featured large, twin recessed scoops that mirrored the look of the grille. Rocker panels were bequeathed bright metal trim. Bulging fenders and radiused rear wheel openings lent a more muscular appearance.

The rear spoiler and GSX sticker. (Photo courtesy of Shelton Classics.)

Available only as a two-door hardtop, the GSX was offered in two colors: Saturn Yellow or Apollo White. A black chin spoiler was included, as were black full-length side stripes, wide black hood stripes, and thin black stripes just above the chrome rockers. On the decklid sat a sculpted rear spoiler. A GSX sticker lived on the rear fenders, and a GSX badge adorned the grille. Racing mirrors came standard.

The interior of the GSX was still typical of Buicks from the period. Instrumentation featured round gauges set into square-shaped pods, and a tachometer sat in a bulge on the hood. The upholstery was a choice of Madrid or Laredo-grain black vinyl over bucket seats. A Rallye steering wheel was standard.

The cockpit. Note the gauges, Rallye steering wheel, and slap-shifter automatic. (Photo courtesy of Hagerty.com.)

Air conditioning, tinted glass, power windows, power locks, four-way power seats, a speed alert, and a choice of radio were all optional. Two floor consoles could be selected from – one for manual cars, and another for autos.

With GM’s edict on the 400 cubic-inch displacement limit finally removed, Buick went hog-wild on the powerplant front.

The GSX was bestowed with a monstrous 455 cubic-inch V8 with a cast-iron crankshaft linked to aluminum pistons by way of forged-steel connecting rods. Bore and stroke was 3.90″ by 4.312″ and worked with a 10.0:1 compression ratio.

The monster 455 cubic inch V8 with Stage 1 Package. (Photo courtesy of Shelton Classics.)

The hydraulic camshaft had a 0.3891/0.4602-inch intake/exhaust lift with a duration of 290/322 degrees, and a dual-snorkel induction system drew cold air from the vents in the hood directly to a Rochester Quadrajet four-barrel carburetor. 2.005″ intake and 1.620″ exhaust valves sucked air/fuel and sent gasses to a dual 2.25-inch exhaust system.

Output was a nearly sarcastic factory rating of 350 horsepower at 4,600 RPM (a more accurate estimate would place it at 390 bhp) and an absolutely astonishing 510 lb-ft of torque at a low 2,800 RPM. Incredibly, the latter figure held the record for most torque in any American car all the way until 2003, when the Dodge Viper’s V10 eclipsed it.

Behind the engine, one could opt for a Muncie four-speed manual with an 11-inch clutch, or a three-speed Turbo Hydra-Matic 400 auto slushbox. Power was transmitted to a 10-bolt, 8 1/2-inch Positive Traction limited-slip differential with a 3.42:1 final drive ratio.

The 15×7-inch, five-spoke wheels wrapped in G60-15 Goodyears. (Photo courtesy of Shelton Classics.)

Heavy-duty axles spun snazzy 15×7-inch, chrome-plated, five-spoke wheels wrapped in G60-15 Goodyears with white lettering. To stop those wheels and tires from spinning were 11-inch, power-assisted, vented front discs and 9.5-inch, cast-iron, assisted drums out back.

Suspension on the GSX consisted of the Rallye Ride Control Package comprised of 450-pound coil springs, stout shocks with 1-inch diameter pistons and a 1-inch anti-roll bar in the front. 144-pound springs, shocks, heavy-duty upper and lower control arms, a .875-inch anti-roll bar, and upgraded bushings in the rear.

All of these mechanical goodies were able to launch the 3,874-pound car to 60 mph in just 5.8 seconds and push past the quarter-mile in 13.38 seconds at 105.5 mph. This was serious performance for 1970 and put the GSX on par with the likes of Hemicudas and Boss 429s in terms of performance.

A gorgeous Apollo White GSX Stage 1. (Photo courtesy of Mecum Auctions.)

In spite of this, Buick actually didn’t stop there with the GSX. Optional, was a sub-$200 dollar (some sources list the price at $115, and others at $199) package known as Stage 1. It bumped the compression ratio up to 10.5:1 and added a more aggressive cam with a .490 lift and longer duration of 316-degrees intake and 340-degrees exhaust. Overlap jumped from the GSX’s 67-degrees to 90.

Stage 1 also added a 3.64:1 final drive ratio, unless the car was optioned with air conditioning, whereupon it remained at the standard GSX’s 3.42:1.

The GSX Stage 1 added a considerable power bump to the already brutal 455, though for insurance purposes, the factory only rated the increase at 10 horsepower and no extra torque. In reality, the increase was likely in the neighborhood of 25 horsepower, pushing the GSX Stage 1’s total well and truly above the magic 400 mark.

Stage 1s fetch a pretty penny today. (Photo courtesy of Mecum Auctions.)

Because the GSX and GSX Stage 1 weren’t released until the latter half of the 1970 model year, sales were anything but brisk. In total, only 678 GSXs were built, with a minuscule 479 of them in Stage 1 form – 280 equipped with the automatic and 199 in row-it-yourself guise.

Owing to these numbers, GSX and GSX Stage 1s sell for big bucks today. How big? Well, they’re nowhere near Hemicuda convertible prices, but a correctly restored, Concours-quality 1970 Stage 1 is worth in excess of $200,000 according to Hagerty valuation.

But is that really too dear a price for a prime example of a Rare Ride? I certainly don’t think so!

About the author

Rob Finkelman

Rob combined his two great passions of writing and cars; and began authoring columns for several Formula 1 racing websites and Street Muscle Magazine. He is an avid automotive enthusiast with a burgeoning collection of classic and muscle cars.
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