The 1970 Buick GSX Built Only 678 Times — And Motor Trend Called It the Quickest American Car They’d Ever Tested

Buick spent most of its history selling comfort, not speed — which made it stunning when Motor Trend called the 1970 GSX the quickest American car they’d ever tested. Built in just 678 examples with a Stage 1 package that delivered more torque than any rival muscle car of its era, the GSX remains one of the most underrated performance cars Detroit ever built. Most people who saw one on the street in period had no idea what they were looking at. Watch to find out why.

Buick built a reputation on comfort and quiet luxury for most of its history — which is exactly what made the GSX such a shock when Motor Trend got one on the dragstrip in 1970. The magazine’s test crew, no strangers to fast cars, came away calling it the quickest American production car they’d ever put through the quarter mile, a claim that seems almost absurd for a brand better known for Roadmasters and Electras. Buick built the GSX in numbers small enough — just 678 for the entire 1970 model year — that most people who saw one on the street had no idea what they were actually looking at.

Buick’s Unlikely Entry Into the Horsepower Wars

The GSX arrived in 1970 as Buick’s answer to a muscle car segment the brand had mostly stayed out of, built on the Gran Sport platform with the biggest engine Buick offered: a 455-cubic-inch V8. In base GSX form it made 350 horsepower, but the real story was the optional Stage 1 package, which bumped output to a factory-rated 360 horsepower and, more importantly, 510 pound-feet of torque — a figure that outmuscled every other muscle car engine on the market at the time, including big-block offerings from Chevrolet, Ford, and Mopar. That torque advantage, more than the horsepower number, is what gave the GSX its reputation as the quietest brand in Detroit’s loudest segment. Buick also offered the GSX as a companion option to the broader Gran Sport lineup, meaning the GSX badge specifically denoted the top-tier appearance and performance package rather than a standalone model line.

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The Motor Trend Test That Changed Buick’s Reputation

When Motor Trend put a Stage 1-equipped GSX through its paces in 1970, the results startled even the magazine’s own testers: quarter-mile times in the low 13-second range, numbers that outran nearly every rival muscle car available that year regardless of badge. The magazine’s conclusion — calling it the quickest American car they had ever tested — became one of the most quoted lines in Buick GSX history, and for good reason. A brand that spent most of the 1960s selling to buyers who valued a smooth ride over a fast one had, almost overnight, built something capable of embarrassing cars from manufacturers with far louder performance reputations.

Only 678 Built — And Most People Never Noticed

Buick produced just 678 GSX models for the entire 1970 model year, a genuinely tiny number compared to the tens of thousands of Chevelle SS, GTO, and Road Runner models sold by rival divisions that same year. Part of that low production came down to Buick’s own limited marketing push and dealer network unfamiliarity with selling a genuine muscle car, and part of it came down to price — a fully optioned Stage 1 GSX carried a premium over comparable big-block muscle cars from other GM divisions. The result is a car that, even new, most buyers never crossed paths with, which is a major reason surviving GSX models command serious money among collectors today.

Saturn Yellow, Apollo White, and Nothing Else

Buick kept the GSX’s color palette deliberately narrow in 1970, offering it exclusively in Saturn Yellow or Apollo White, both paired with bold black stripes running the length of the hood, trunk, and rear spoiler. That restraint was unusual for the era, when muscle car buyers could typically choose from a dozen or more available exterior colors, but it gave the GSX an unmistakable visual identity — a car that announced exactly what it was from a block away, in stark contrast to how quietly it could be optioned inside a Buick showroom otherwise built around comfort and chrome.

A Hood Tach and a Rear Spoiler Signaled the Intent

Standard GSX equipment included a hood-mounted tachometer positioned directly in the driver’s line of sight, a rear spoiler, and a functional dual-scoop hood — details that made clear this wasn’t a dressed-up Skylark but a purpose-built performance model. Combined with Buick’s Stage 1 suspension package, heavy-duty cooling, and a 12-bolt rear end capable of handling the 455’s torque output, the GSX represented a genuine engineering commitment from a division that could have easily phased out the muscle car segment as an afterthought rather than building one of its most respected entries.

Why the GSX Still Gets Overlooked

Despite the Motor Trend endorsement and genuine performance credentials, the GSX has historically sat in the shadow of better-known muscle cars from Pontiac, Chevrolet, and Mopar — partly because Buick’s overall brand image never fully shed its reputation for comfort over speed, and partly because such low production numbers kept the car out of most enthusiasts’ direct experience. That relative obscurity has started shifting in recent years as collectors rediscover just how genuinely quick a Stage 1 GSX was in period, but it remains one of the more underrated entries in the entire muscle car era.

A Legend Built on 510 Pound-Feet

What ultimately defines the GSX’s legacy isn’t the horsepower figure on the window sticker — it’s that 510 pound-feet torque number, which no other muscle car of the era matched, and the Motor Trend quarter-mile numbers that backed it up on the strip rather than just on paper. For a brand that built its identity on quiet comfort, producing the quickest American car a major magazine had tested that year was a genuine surprise, and it’s exactly why the GSX has earned a devoted following among collectors who know the real story behind Buick’s most unlikely muscle car. More than five decades later, that combination of rarity, torque, and a magazine record that still gets quoted is exactly why a genuine 1970 GSX Stage 1 now commands prices that would have stunned Buick’s own sales department in period.

The Stage 1’s Legacy in Buick’s Later Muscle Cars

The GSX wasn’t Buick’s last word on performance — more than a decade later, the division returned to the horsepower conversation with the turbocharged Grand National and GNX of the mid-1980s, cars that, like the GSX before them, dramatically outperformed Buick’s staid reputation. That pattern of Buick occasionally producing a genuine performance shock, separated by long stretches of comfort-focused models, makes the GSX’s story feel less like an isolated anomaly and more like the first chapter in a recurring theme. Enthusiasts who trace that lineage tend to view the 1970 GSX as the original proof that Buick’s engineers could out-build rivals whenever the division actually decided to try.

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