Buick’s 1970 GSX Out-Torqued the Hemi ‘Cuda by 20 Lb-Ft — Then Almost Nobody Bought One

The 1970 Buick GSX and Hemi ‘Cuda came out of opposite corners of Detroit’s muscle car playbook: one built for country-club buyers, the other stripped down for the strip. A rediscovered Muscle Car of the Week rivalry video puts their numbers side by side, and the torque column says more than either brand ever advertised.

Buick was not supposed to build a car that scared the neighbors. In 1970, it did anyway. The GSX bolted a 455-cubic-inch Stage 1 V8 rated at 510 lb-ft of torque into a Skylark-based body wrapped in bucket seats, a rear spoiler, and a hood tach — and it did it while wearing the same badge as your dentist’s sedan. Down in Highland Park, Plymouth was solving the same problem from the opposite direction, building the Hemi ‘Cuda as a raw, stripped-out street fighter with none of the GSX’s country-club pretense. A recent Muscle Car of the Week episode revisits that rivalry, and the numbers underneath it explain why gearheads are still arguing about it more than fifty years later.

The GSX didn’t come from a clean sheet of paper. It grew out of Buick’s Gran Sport line, which had been chasing performance credibility since the mid-1960s without ever fully shedding its reputation as the muscle car for buyers who also wanted air conditioning and a soft ride. For 1970, General Motors finally lifted its longstanding 400-cubic-inch displacement cap on intermediate cars, and Buick used the opening to drop a full 455 into the Gran Sport for the first time — the same displacement ceiling Chevrolet, Oldsmobile, and Pontiac were racing to fill with their own big-inch engines that same model year. The GSX was Buick’s loudest answer to that new freedom: bold two-tone stripes, a domed hood scoop, a rear spoiler, and a hood-mounted tachometer that told anyone paying attention exactly how serious the car underneath actually was.

The Video Puts Detroit’s Two Different Answers Side By Side

The episode frames the GSX and the Hemi ‘Cuda as cars built for completely different buyers, even though both wound up on the same drag strips. As the video’s own description puts it, the Buick was engineered to compete against “higher end, feature rich cars,” while the ‘Cuda targeted the pony car crowd going after Camaros and Mustangs. That’s not a small distinction — it shaped everything from the interior trim to the way each car was marketed, and it’s the reason so many owners in the comments describe the choice between them as almost a personality test.

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Host Kevin walks through how the rivalry actually started, and the video leans on period road tests and dealership positioning to make the case that Buick wasn’t just building a fast car, it was building an argument that a luxury division could out-torque anything Chrysler or GM’s own performance brands put on the showroom floor. One commenter who drove a new GS 455 Stage 1 when it was “almost new” backed that up bluntly: he said it would run off the showroom floor like nothing else in 1970, and that it “never got beat” against the lightweight competition he raced it against — while getting an unimpressive 10 mpg for the privilege.

The Torque Number Buick Didn’t Want to Print Too Loud

On paper, the two cars weren’t close. Buick’s factory rating for the GSX Stage 1 455 was 360 horsepower and 510 lb-ft of torque, a torque figure that topped the Hemi ‘Cuda’s advertised 490 lb-ft from its 425-horsepower 426 Hemi. Both manufacturers were playing the same game with those numbers, though — Chrysler was widely understood to have underrated the Hemi to keep insurance premiums from spiraling, with dyno testing on stock 426 Hemis showing readings well north of 490 horsepower. Buick’s Stage 1 455 carried the same reputation among period racers and, later, NHRA classers, who generally figured the real output was closer to 400-plus horsepower rather than the printed 360.

What nobody disputed was the torque delivery. The Stage 1 455 made its 510 lb-ft at a lazy 2,800 rpm, which is why Buick’s own engineers reportedly worried about clutch and driveline durability more than they worried about outrunning a ‘Cuda in a straight line. It’s also why the GSX earned the “torque monster” reputation that still follows it, a description more than one commenter on the video used without any prompting.

Why Buick Only Built 678 of Them

Here’s the part that turns this from a spec-sheet argument into a genuinely rare-car story: Buick built only 678 GSX models for the 1970 model year, split between 491 finished in Saturn Yellow and 187 in Apollo White. Of those, just 400 were ordered with the 455 Stage 1 package that made the torque numbers real — the rest carried the standard 455, still potent but without the Stage 1’s hotter cam and other tweaks. That’s a vanishingly small production run for a car built to fight the Hemi ‘Cuda, which itself wasn’t exactly common but still outsold the GSX handily.

The price tag explains a lot of that gap. The GSX package stacked onto an already expensive Gran Sport, and Buick dealers weren’t set up to move big volumes of a drag-strip special with a luxury price. Plymouth, by contrast, was selling the Hemi ‘Cuda through a performance-focused dealer network that had spent years building an audience willing to pay for a raw, four-speed street brawler with none of Buick’s creature comforts.

Two Different Cars, One Argument That Never Ended

What makes the GSX-versus-‘Cuda debate stick around isn’t just the numbers, it’s that owners still can’t agree on which car actually deserves the crown. In the comments under the video, self-described “diehard Mopar” fans admit the GSX would be the one GM car they’d own, while others say the Hemi’s switch to a hydraulic valvetrain in 1970 made it the more streetable — and therefore the better — muscle car of the two, even with less torque on paper. One commenter who owned a GSX at 17 years old summed up the appeal simply: a tire-shredding big-block wrapped in a car nobody expected to be that fast.

If a $4,000-plus luxury muscle car from 1970 is out of reach, the cheap way into a period-correct GM V8 doesn’t have to start with a GSX — the Chevelle SS everyone chases isn’t the only V8 GM built that decade, and there are cheaper doors into the same era.

Watch the full video above and let us know your thoughts in the comments.