With the 455 in³ motor, the GSX had a higher torque rating than any other production muscle car. This made it one of the fastest Buicks both on and off the 1/4 mile. Motor trend called it “the quickest American production car we had ever tested.” There’s no doubt that the GSX was built compete against cars like the Pontiac GTO Judge, Oldsmobile 442 W30 and Chrysler’s HEMI ‘Cuda.

For $199, Buick offered a Stage I package that used a different camshaft, stronger springs and ported heads to offer more power. Rated at only 360 hp, the figure is much closer to 400 in reality.

The GSX built upon these upgrades by offering the Stage I package with a hood-mounted tachometer, Hurst shifter, Polyglas G60xl5 tires, front disc brakes and a heavy duty suspension. This came at the steep price of $1,196 over and above the cost of a 455 Buick GS.

In 1970 Buick built 678 built of the GSX in either Apollo White or Saturn Yellow. In 1971 became an option on the Gran Sport and opened up the doors for many new colors.