The arrival of the new compacts by the Big Three in 1960 was the beginning of a major new era. The race for sales also turned into a literal race, when NASCAR created a new Compact Sedan Class and invited the Little Three to Daytona for the 1960 races. All three accepted, and quickly developed “speed kits” or such, to be sold by dealers in order to homologate the cars. But Chrysler not only took the challenge more seriously than the other two, they also were starting with a significantly more powerful motor, the new 170 cubic inch slant six. The Valiants took the top seven finishing posts, as seen in this picture, the winning car averaging 122.282 mph on the banked oval. A Falcon came in eighth, and the top Corvair in ninth. Zora Arkus Duntov was not happy that day.
The base 170 inch slant six was the most powerful of the the new 1960 compacts, but it also had the greatest performance potential due to its excellent breathing characteristics. Chrysler’s performance division quickly exploited that with the Hyperpak, a $400 option that included a very long-runner aluminum intake manifold topped by a Carter AFB four-barrel carb, that had took advantage of the resonant ram effect to boost torque at 4500 rpm, perfect for powering out of corners.
A number of other performance parts were included too, and resulting engine was rated at 148 hp by the factory. It’s generally accepted that it produced somewhat more than that on race day, considering the 130 mph top speed that the Valiants pulled, running at some 6600 rpm.
The winning Valiant driven by Marvin Panch also averaged 88.134 on the road-course race.
Here’s a shot of a Valiant passing two Corvairs and a Falcon.
A couple of Falcons drafting in order to both increase their speed. It wasn’t enough though. The Ford “speed kit” included a number of performance items for the 144 inch six as well as chassis parts, but didn’t have the extensive development time and budget that Chrysler invested into the Valiant program.
The Corvair program suffered from the same limitations. Duntov said there wasn’t enough time to do a proper four-carb setup on the Corvair engine, which is what it needed, and eventually got, for production versions too. This picture clearly shows how the rear-engine Corvair is “working” its rear tire, in a classic mild oversteer pose. Needless to say, the Corvairs were treated to a full suspension upgrade, including the front sway bar and rear anti-camber spring that was left off the production 1960 Corvairs.
In 1961, the Tempest also got into the act, with its half-of-a-V8 slant four, and all the performance parts that would also fit on the Super Duty V8s. And a Lark showed up in 1961, presumably with the V8? But NASCAR pulled the plug on the series after a couple of years, and six cylinder performance efforts by the factories soon went into terminal slumber, with a few exceptions.
More on the Hyperpak six at allpar.com