Following on the heels of the exciting, limited-production Bonneville of 1957, Pontiac introduced its famous “Wide Track” chassis layout for 1959, creating the best-handling full-size cars in the industry. From this point, Pontiac firmly established itself as GM’s high-performance division with scores of victories on NASCAR ovals and drag-strips alike, in spite of the infamous AMA racing ban that discouraged most American manufacturers from direct involvement in racing.
Pontiac high-performance development accelerated even further in 1960, spurred on by four NASCAR Grand National victories, Mickey Thompson’s quadruple Pontiac V-8 Challenger land-speed record car and Jim Wangers’ NHRA Top Eliminator drag racing title. In 1961, Pontiac grabbed an incredible 21 NASCAR Grand National victories, and the full-size Catalina Super Stock drag racing car was unleashed late that year.
The heart of the Super Stock package was the 421-cubic inch Super Duty V-8 engine, an enlarged variant of the SD 389, with 405 vastly underrated horsepower. Both SD engines were originally dealer-installed options, but since the NHRA moved to limit racing eligibility to factory-available options on cars available to the public, Pontiac made the SD 421 a factory option for 1962, with most of the approximately 164 SD 421 engines installed in the Catalina and another 16 in the upscale Grand Prix.
Built for high-rpm, severe duty as implied by its name, the SD 421 was based on a four-bolt main block with a tough forged crank, Mickey Thompson forged aluminum pistons and forged-steel connecting rods. A hot flat-tappet solid-lifter camshaft and valvetrain, free-flowing cylinder heads, large-diameter valves, 11.0:1 compression, dual Carter four-barrel carburetors and special exhaust manifolds with racing cutouts rounded out the SD 421 engine.
The SD 421 included a heavy-duty driveline including the clutch and pressure-plate, and available transmissions included a heavy-duty three-speed manual unit, or the Borg-Warner T10 four-speed in the Catalina, with only the four-speed available in the Grand Prix. Only a 4.30:1 rear-axle ratio was available, while a limited-slip differential remained optional. A variety of other high-performance options were available, including Pontiac’s unique eight-lug aluminum wheels and a variety of lightweight aluminum body components.
This car was auctioned off by RM Auctions in November of 2010 at the Robson Estate, Gainesville, Georgia.
405 bhp, 421 cu. in. Super Duty V-8 engine, dual Carter four-barrel carburetors, four-speed Borg-Warner T-10 manual transmission, independent front suspension with unequal-length A-arms and coil springs, semi-floating rear axle with coil springs, and four-wheel hydraulic drum brakes. Wheelbase: 119"