The early years of the 1960s were time-stamped with the mark of the dinosaurs—behemoth 1962 406 Galaxies, 421 Pontiac Catalinas, and 409 Chevrolet Impalas stomped the earth. On the dragstrip, these big-block production cars attracted crowds nearly as large as those for the much faster and much noisier purpose-built dragsters. Each marque's true believers wanted to see their chosen brand stomp the competition.
Hayden Proffitt won class at the 1962 Winternationals, and that included a nearly 4-foot-t
The American Manufacturers' Association's (AMA) 1957 ban on racing had thankfully lost support (because performance was selling!), and Pontiac was enjoying the fruits of conquering the competition on NASCAR oval tracks and the NHRA's increasingly popular dragstrips. On the street, It was often a 389ci Pontiac, not a Chevrolet, that the fast guys were wheeling. Guys like Don Gay were winning races with A/Stock Pontiacs, and you could drive that same Catalina right off the showroom floor.
In the 1960s, there was no more inventive car crafter than Mickey Thompson. So it was not surprising that he persuaded the suits to let him champion the Pontiac name into the record books. In 1960, Thompson had been the first man on earth to hit 400 mph with a streamliner powered by four normally aspirated Pontiacs. It wasn't a world record because the car broke on the return run, but he was still fast.
This undercarriage shot reveals an effort to fit a B&M hydro transmission to the car,
Unfortunately, while the streamliner effort revealed Pontiac power, it didn't promote production cars, which was really what Pontiac wanted. Thompson already knew how to win races; all he needed was the right car. If there is one unalterable rule for building a performance car, it's that you put the strongest engine in the lightest car. In late 1961, Pontiac shared something new with Thompson, a brand-new car called the Tempest. It was Pontiac's version of the new GM compact car, similar to the Buick Special and Olds F-85. With its four-cylinder engine, the Tempest weighed 2,785 pounds and rode on a short 112-inch wheelbase that looked miniscule compared to a Wide Track Catalina that outweighed it by nearly 900 pounds. The 1961 Tempest attracted no attention from drag racers because of its weak slant-four engine, which was one-half of a 389. The Tempest also came with a weird swing arm independent transaxle assembly, first used on the Corvair. This fact alone placed it neatly into leper status with performance buffs. Who would want a 1961 Tempest when you could buy a tri-power 389 Catalina or a 409 Chevy? But the fates were aligning in Thompson's favor, when he connected the dots to a brand-new NHRA drag racing class called Factory Experimental.
A/FX allowed Super Stock–legal engines to be transplanted into any car of the same marque. It was as if NHRA was inviting Thompson to stuff Pontiac's vaunted, twin four-barrel Super Duty 421 engine into this lightweight chassis. The only other real contender was the Chevy II with a transplanted 327 and a four-speed—Chevy didn't get the hint for production until 1965—and Tasca Ford was still months away from prototyping its 427 Fairlane.
Proffitt used a fullsize Pontiac rear axlehousing and narrowed it to fit under the Tempest
Thompson enlisted Hayden Proffitt to cut up a new Tempest that Hot Rod magazine quickly chronicled ("Thompson's Terrible Tempest") in the Sept. 1962 issue. Proffitt immediately removed the clumsy two-speed transaxle and replaced the spindly piece with a more traditional manual transmission and a narrowed, fullsize Pontiac rear axle. The Super Duty 421ci engine actually fit into the Tempest's engine compartment; that was the easy part. The factory transaxle configuration required only a small hump in the floorpan for clearance and was otherwise nearly flat, prompting Proffitt to cut much of the floor to clear the traditionally located heavy-duty Pontiac three-speed manual transmission. Thompson showed up at the NHRA Winternationals with Proffitt driving and cleaned house, while running low 12s. That got everybody's attention. By the Indy Nationals in September, there were several Tempests in attendance, but Lloyd Cox drove the Thompson entry, and once more the team took the A/FX class trophy.
Among the SD 421 components were these now ridiculously rare, long-tube factory cast-alumi
The major fabrication work was performed at the rear of the car, and it began when Proffit
As you can see, the 421 Super Duty was an easy fit in the Tempest engine bay. Left-side he
Here, we see the sheetmetal work required to adapt a manual transmission underneath the st
It may not look like it, but this is the interior of a class-winning A/FX Pontiac in 1962.
According to the Hot Rod story, the only changes to Mickey Thompson’s stock 421 Super Duty