At the height of the muscle car wars, torque was king and no competitor could dethrone the 510 lb.-ft. of twist generated by the GSX’x available 455 Stage I V-8 engine. In a 1970 road test, Motor Trend went from 0 to 60 mph in 5.5 seconds and covered the quarter-mile in 13.4 seconds. The GSX’s combination of raw power and Buick’s signature luxury prompted many to describe the car as a “velvet hammer.”