Buick GSX Stage 1 455

Buick GSX Stage 1 455

The 1970 Buick GSX is one of the most underappreciated muscle cars ever built, despite being one of the fastest. Its 455 Stage 1 engine produced a factory-rated 360 hp and a staggering 510 lb-ft of torque — the highest torque rating of any muscle car in the era. Car magazines of the time routinely recorded sub-14-second quarter miles and 0-60 times under 6 seconds.

The GSX (Gran Sport Experimental) was the top-dog variant of the Buick Gran Sport, itself the performance version of the Skylark. It came in only two colors for 1970: Apollo White or Saturn Yellow, both with bold body-length racing stripes, a hood-mounted tachometer, front and rear spoilers, and unique GSX badges.

The Stage 1 engine package was the key to the GSX's performance. It featured a more aggressive camshaft, larger valves, special heads with improved porting, and a recalibrated Rochester Quadrajet carburetor. The torque output was so massive that the car could break traction on dry pavement in any gear. The Stage 1's real-world power was estimated at 400+ hp by contemporary testers who believed Buick was severely underrating the engine to keep insurance premiums down.

Only 678 GSXs were produced in 1970 (488 in Saturn Yellow, 190 in Apollo White). Of those, approximately 400 had the Stage 1 engine. This makes the GSX one of the rarest mainstream muscle cars produced during the peak of the muscle car era.

The 1971 GSX lost the unique color restrictions (now available in any Buick color) and received lower compression ratios due to new emissions standards. The 1972 model was the last, with further detuning. The 1970 remains the definitive GSX and one of the most powerful American cars ever rated in the muscle car era.