While most people associate Pontiac performance in the early part of the 1960s with the 389 there was another engine that truly proved to be the brand’s beast. The mighty Pontiac 421 was a star on the drag strip and a super nova on the Nascar tracks of the first half of the 60s. Released in 1961, the 421 was a bored and stroked 389 which sported a bore of 4.094″ and a stroke of 4.00″. The other major difference between the “typical” Pontiac engine of the time was that this one used the large journal block with the 3.25″ mains and four bolt main caps. There were production 421s and then there were the Super Duty 421s.
The Super Duty engines got forged steel cranks and forged steel rods. If it was heading for NASCAR the engine got a single 4bbl carb and intake setup and if it were heading to the drag strip it got a dual 4bbl setup. It was not until the 421 street engines hit the showroom floor and they would be in production (with lesser horsepower output than the full kill versions) until 1966. The street engines carried a high horsepower rating of 376, which was conservative. The SD engines produced nearly 500hp. We’d have to guess that the street engines were 400hp performers on a bad day.
The interesting things that the SD engines had were stuff like aluminum cast exhaust headers and the radical for the time #10 McKeller mechanical lifter camshaft. As you will hear in the first video below, these engines sounded pretty gnarly. In today’s world we have completely bonkers camshafts out there for purchase but in the early 1960s this was some pretty ragged edge stuff. The thing had 308 degrees of intake duration and 320 on the exhaust side.
Lots of 421s powered Catalina 2+2s, Bonnevilles, and Grand Prix models over the years. Of course if you have real money to spend you’ll hunt down a Super Duty Tempest, a Super Duty Catalina, or a Super Duty Ventura. These cars were horrifying to see pull into a drag strip if you were driving anything else. During the 1961 season Pontiac won 30 out of 52 races that year. In 1963 a Super Duty Tempest leveled a field of cars that included a Mystery Motor Corvette, and at least one Ferrari 250 GTO at Daytona.
These are awesome engines.