1970 Buick GSX '70 Buick GSX reigned as the most powerful muscle car


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1970 BUICK GSX - 455 ENGINE - 1 OF ONLY 678 PRODUCED. '70 Buick GSX reigned as the most powerful muscle car ever built in America. Three hundred fifty horsepower doesn't flip your wig, even though it was famously underrated. But it's the torque rating that set the bar with 510-lbs.ft.; it took the 8.0-liter V-10 in the '92 Viper to top it. Getting there, though, required just a bit of an upgrade from the 400-cu.in. engine that had been the strongest midsize Buick offering since 1967. Buick performance had been brewing, slowly, for years, since the marque introduced its new big-block 400 and 430 in 1967, but still, no one expected very much from them. The GS 400's 400 was always torquey, but was not selling horsepower. And then GM just kind of went bonkers. When corporate lifted an internal ban on putting big engines in medium-sized cars, Buick immediately dropped the 455 in, keeping the GS in competition with so many other GM muscle cars, like the GTO, LS-6 Chevelle and W-30 Oldsmobile. Buick derived the 455 directly from the same architecture as the 400, using the same nodular cast-iron crank with its 3.90-inch stroke, but increasing the bore diameter to 4.31 inches (the 430 had used a 4.1875-inch bore); a hydraulic camshaft and a Rochester four-barrel on iron heads were found in all '70 455 applications. Somehow, the same engine that was rated at 350hp in the GS455 made 370hp in a LeSabre or Wildcat; meanwhile, the NHRA rated the Stage 1 at 400hp based on ETs against a rated 360, so you can infer that something a bit better than 350hp was actually installed in a base-engine GSX. GSX came in Saturn Yellow or Apollo White with identical graphics: callouts on the rear quarters; awesome badge on the blacked-out grille; black stripe carried onto a spoiler apparently hewn from the living rock. This was not a plastic piece, and you couldn't get it on anything but a GSX; there are fakes, but they're fairly easy to spot today--they weigh less, and the car should have a unique torsion spring in the trunk to hold the lid open with the extra weight. With a lip spoiler in front and a tach on the hood, this is a dynamic looking machine: the zingiest Buick of them all. Did the aero aids work? Who knows? Buick was so busy pushing the Stage 1 to the press that no one seems to have road-tested a standard GSX. Hot Rod took a Stage 1 GS with a TH400 to a 14.4-second quarter mile at 96 MPH, and you can find ample reports of low-13 quarters and high five-second 0-60s from the day. In the mid-Eighties, Popular Mechanics found 13s from a Stage 1 GS455 with nothing more than a switch to radials, although there was no GM muscle car with more meat than the G60-15s that came standard on a GSX. The Stage 1 engine brought with it a 3.64:1 rear gear ratio, in both the GS455 and the GSX, regardless of whether it used the TH400 or the four-speed; Stage 1 cars with A/C received 3.42 gears, as did base 455 models. That may have hurt off the line, but Car Life saw 129 MPH in a GS455.
1970 Buick GSX '70 Buick GSX reigned as the most powerful muscle car
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1970 BUICK GSX - 455 ENGINE - 1 OF ONLY 678 PRODUCED. '70 Buick GSX reigned as the most powerful muscle car ever built in America. Three hundred fifty horsepower doesn't flip your wig, even though it was famously underrated. But it's the torque rating that set the bar with 510-lbs.ft.; it took the 8.0-liter V-10 in the '92 Viper to top it. Getting there, though, required just a bit of an upgrade from the 400-cu.in. engine that had been the strongest midsize Buick offering since 1967. Buick performance had been brewing, slowly, for years, since the marque introduced its new big-block 400 and 430 in 1967, but still, no one expected very much from them. The GS 400's 400 was always torquey, but was not selling horsepower. And then GM just kind of went bonkers. When corporate lifted an internal ban on putting big engines in medium-sized cars, Buick immediately dropped the 455 in, keeping the GS in competition with so many other GM muscle cars, like the GTO, LS-6 Chevelle and W-30 Oldsmobile. Buick derived the 455 directly from the same architecture as the 400, using the same nodular cast-iron crank with its 3.90-inch stroke, but increasing the bore diameter to 4.31 inches (the 430 had used a 4.1875-inch bore); a hydraulic camshaft and a Rochester four-barrel on iron heads were found in all '70 455 applications. Somehow, the same engine that was rated at 350hp in the GS455 made 370hp in a LeSabre or Wildcat; meanwhile, the NHRA rated the Stage 1 at 400hp based on ETs against a rated 360, so you can infer that something a bit better than 350hp was actually installed in a base-engine GSX. GSX came in Saturn Yellow or Apollo White with identical graphics: callouts on the rear quarters; awesome badge on the blacked-out grille; black stripe carried onto a spoiler apparently hewn from the living rock. This was not a plastic piece, and you couldn't get it on anything but a GSX; there are fakes, but they're fairly easy to spot today--they weigh less, and the car should have a unique torsion spring in the trunk to hold the lid open with the extra weight. With a lip spoiler in front and a tach on the hood, this is a dynamic looking machine: the zingiest Buick of them all. Did the aero aids work? Who knows? Buick was so busy pushing the Stage 1 to the press that no one seems to have road-tested a standard GSX. Hot Rod took a Stage 1 GS with a TH400 to a 14.4-second quarter mile at 96 MPH, and you can find ample reports of low-13 quarters and high five-second 0-60s from the day. In the mid-Eighties, Popular Mechanics found 13s from a Stage 1 GS455 with nothing more than a switch to radials, although there was no GM muscle car with more meat than the G60-15s that came standard on a GSX. The Stage 1 engine brought with it a 3.64:1 rear gear ratio, in both the GS455 and the GSX, regardless of whether it used the TH400 or the four-speed; Stage 1 cars with A/C received 3.42 gears, as did base 455 models. That may have hurt off the line, but Car Life saw 129 MPH in a GS455.

Additional information

Make: Buick
Model: GSX
Type: Coupe
Year: 1970
Doors: 2
Mileage: 67828
Engine size (cc): 455
Transmission: Automatic
Fuel Type: Gasoline
Interior Color: Black
Exterior Color: Yellow
Vehicle Identification Number: 44637OH273808
United States, California, San Jose
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