The 1970 Buick GSX was available offering a Stage 1 optional performance pack for the Grand Sport 455 for one year only with ’72 and ’73 offering a similar package for any of the Grand Sport vehicles.
The last year for the 455 big-block was 1974 when Buick dropped it entirely from its power arsenal. Buick wanted a piece of the muscle car market that was booming with the other guys’ models having names like the Judge, GTO, and 442 taking a large chunk of the action on the sales floor. The luxury-appointed GSX was how Buick Division responded. The car was marketed with aggressive advertising slogans like “A Brand New Brand of Buick” and “Light Your Fire Cars from Buick” to pick up lagging sales. Only 278 GSX models equipped with the base 455 sold the first year, and enthusiasts ordered 400 with the Stage 1 performance pack.
That means a maximum of 678 units are out there less the ones that got scrapped. The only competition for the GSX in the ’70 model year was the Hemi ‘cuda with about the same power, but the GSX carried less weight. Which of the two was faster? They were very close, for sure, but there was a big uproar in the ’80s caused by an article in a major magazine claiming the GSX Stage 1 was the quicker of the two. There was also a Stage 2 dealer option that was exceptionally rare, but there are no statistics on how many of those GSX’s had this ultimate performance package.
The power train of the GSX starts with the basic GS 455 (7.4L) V8 engine. Equipped with the four-barrel Quadrajet carburetor, it produced 350hp (260 kW) and 510 lbs.-ft. (690 N-m) torque at 2800 rpm. The Stage 1 option was still equipped with the four-barrel, but this package has a more zealous ignition timing, dynamic camshaft, higher compression with distinctive head design, and larger intake and exhaust valves. All the GSX versions came with a choice of the Turbohydromatic 400 or the Muncie M-22 “rock crusher” four-speed transmissions except for one unit, and this one of a kind convertible had a three-speed manual with the standard equipment 3.64:1 Positraction axle ratio. Any of the ’70 vintage GSX’s with air conditioning had a different 3.42 axle ratio.
Should you think you’ve come across a GSX very rare Stage 2 dealer option pack, you can identify it by the Edelbrock B4B aluminum intake, Holley carburetor, D-port exhaust Stage 2 heads, “Kustom” headers, and other racing equipment, the obvious differences. Unseen differences include an aggressive cam, higher compression forged pistons, hollow push rods, with some calibration changes for the ignition and carburetor. The goodies vary slightly for each Stage 2 option, and they were shipped from the factory in the trunk of the vehicle.
The 1970 GSX was available only in two colors; Saturn Yellow and Apollo White, with a wider range of colors to choose vfom in succeeding years. The car came with a distinguishing, thin, full-length body strip outlined with red pinstriping running down the sides and across the rear spoiler. Two wide black stripes also ran the length of the hood through the front spoiler.
The car has a hood-mounted tachometer, which is a feature that Buick engineers disliked because the owner had to purchase it from the Pontiac division. Also included as basic standard equipment on the GSX were bucket seats with the stick shift mounted in the center console. Handling features include close-ratio steering, wide oval tires, front and rear sway bars also as basic equipment on the GSX.
Should you decide to purchase a restored model, there were four sold at the Barrett-Jackson auction in Las Vegas for $80,000 in 2010.So you should have your pockets full if you’re looking to drive one of these classics.