NHRA - National Hot Rod Association


4/21: Not just a date, but a legendary 421-cid Pontiac that changed drag racing forever—Footage and photos!

In the early 1960s Detroit was in a horsepower war. With nearly a dozen car brands offered by the Big Three automakers, the competition for sales was brutal—even between divisions.
21 Apr 2020
David Kennedy

How did Chevrolet, Ford, Plymouth, and Pontiac make their cars stand out and sell in such a competitive marketplace? Simple, they won races.

One of Detroit’s masters of selling performance was an auto executive named Semon “Bunkie” Knudsen. An engineer by education, Knudsen ran Pontiac, Chevrolet, and Ford during the creation of many of those brands’ most iconic muscle cars. In 1961, Knudsen’s Pontiac was entering a world of 409-cid Chevys, 406-cid Fords, and 413-cid Mopars. He knew Pontiac’s 389-cid engines were going to be outgunned on the track. So right before the 1961 NHRA U.S. Nationals, the following announcement was made:

“Pontiac is now offering to qualified drivers a 421 cubic inch high-performance engine option. The engine is rated at 373 horsepower and features dual four-barrel carburetors, a solid-lifter camshaft, and high-capacity aluminum exhaust manifolds. The 421 engine is available only with related heavy-duty driveline components. It can be fitted to any Catalina or Ventura 2-door model.”

Immediately Pontiac was back on top. It was offering an over-the-counter motorsport weapon system that would come to be known as the 421 Super Duty package. Engine production started in 1961. At first it was a race-only drag car upgrade, but it grew into a complete car for buyers in the know.

It’s thought the OS/S* class 1961 Pontiac Catalina built by Mickey Thompson and driven by Hayden Proffitt at the 1961 NHRA U.S. Nationals in Indy (you can watch the 421-cid Pontiac win at 18 minutes and 40 seconds into the footage below) was the first time the world saw the 421-cid Super Duty in competition.

While Pontiac rated the 421-cid Super Duty at 405 hp, Motor Trend tested a 421-cid car in a 1962 article and determined it made 465 hp and 505 lb-ft at the flywheel. A confidential internal memo dated September 11, 1962, from Vince Piggins (Chevrolet’s head of Economy, Safety and Performance Department) to Zora Arkus Duntov (and others) said the “Pontiac 421 cu. in. engine for 1963 is reported to be putting out 500 ft-lbs torque at 4,200 rpm and 468 hp at 5,800 rpm [with] single 4-bbl carburation. Smokey [Yunick] verifies the 40hp increase has been made for 1963.”

The 421-cid Super Duty engine came with twin Carter 500-cfm carbs and an aluminum intake manifold. Aluminum exhaust manifolds were optional but were known to melt under intense hot lapping. Smokey Yunick reported the aluminum manifolds were done after 10 laps on a NASCAR track.

How did Chevy, Ford, and Mopar respond? You’ll have to check back with NHRA.com on April 26 and April 27 to find out.

*In 1962 the OS/S class went on to become the FX class.