Muscle Cars - Buick GS Stage 1

buick gs stage1 grillesThe Buick Gran Sport or GS was a high-performance option package available on a number of Buick models, including the Riviera, Skylark, and Wildcat. A special version of one model was given the package's name as its model name. As with all American engines produced prior to the 1972 model year, these were SAE gross ratings, which are generally significantly higher than SAE net ratings, which are indicative of what actual production engines produce in their "as installed" condition (with all engine accessories and full exhaust system in place). Magazines from the period obtained trap speeds in the 105 mph range for the 1970 test cars provided to the press, leading some to suggest the engine was truly "under-rated", relative to what was typical for the time.

Road tests of this engine suggested the engine produced in at least 420 hp. Many magazine road test editors commented on the unbelievable torque this engine produced and its ability to easily spin the tires. The Stage 1 engine option consisted of a more aggressive camshaft,higher compression, unique cylinder heads, unique 4 barrel carburetor, more aggressive ignition timing,5/8 inch oil pickup tube and a higher numerical final drive. The engine was available with either a firmer shifting Turbohydromatic 400 and a standard 3.42:1 limited slip rear differential. A 3.64:1 rear ratio was standard when delivered with a Stage 1 without air conditioning.

buick gs stage1 tail lightsThe relatively unknown, very expensive, and very rare, 1970 GS 455 Stage 1 drew a great amount of attention and controversy in the muscle-car world when in the 1980s it was listed as faster than any of the Chrysler Hemi cars in the original "50 fastest muscle cars" list. This Hemi vs. Stage 1 controversy has prompted several contests to settle the issue; it remains an unsettled matter and has been a great boon to car magazine sales over the years. There was also a rare Stage 2 option produced. This was a dealer-installed package (what was known as a "dealer option"), first offered in 1969. It included a cam, headers, intake manifold, high compression forged pistons, hollow pushrods, and some calibration changes to the ignition and carburetor.

If the car was ordered with the Stage 2 package, the parts were shipped in the trunk of the car. In 1970 the Stage 2 package included special D- Port exhaust port Stage 2 heads, matching Kustom brand headers, a radical cam, high compression forged pistons, Edelbrock B4B aluminum intake, Holley carburetor, and other equipment for racing. Few Stage 2s were ever used on the street and Buick only ever factory assembled 15 Stage 2 test units. One of which was a factory GSX test mule with 4 speed manual transmission used for speed testing. That GSX test mule was equipped with 4.78 gearing and was driven on the streets and tracks on the west coast.

buick gs stage1 wheelsThe Stage 2 package's existence was not made public until 1972 when the Stage 2 parts could be ordered in any combination. There is little documentation about the 12 Stage 2 cars that were sold. One was campaigned by Kenne-Bell/Reynolds Buick and the other was known as the Jones-Benisek car. The Jones/Benisek car is known to have been delivered as a Stage 1 car with all the Stage 2 components in the trunk in GM boxes. Output and sales for the assembly-line cars were down after 1970 largely due to reduced engine compression ratios and a change from gross to net horsepower ratings. In later years, air quality regulations further limited the power in part due to the addition of catalytic converters and single exhaust pipes.

However, Stage 2 parts were available over the Buick parts counter although the Stage 2 heads were discontinued after about 75 sets were produced. The discontinuation was due to porosity problems with castings.The discontinuation of the Stage 2 also was due to the ever tightening emission standards which resulted in lower performance. GSX / GSX Stage1 was the optional high performance package available on the GS 455 starting in 1970. The GSX was made to attract attention and to help showroom traffic in an effort to increase sales. The GSX was Buick's answer to Pontiac's GTO Judge and Buick advertised it as "A Brand New Brand Of Buick" and "Another "Light Your Fire Cars From Buick".