The iconic sports car will be offered at the RM Sotheby’s Arizona auction on January 25.

The formula was not necessarily a new one. Hot-rodders had been stuffing big engines in 1932 Deuce Coupes long before Carroll Shelby shoehorned a Ford small-block V-8 into a lightweight British sports car called the AC Ace roadster. Powered by an inline-six engine, it was the perfect subject for a British-American hybrid that would take motorsport by storm and put Shelby, and his cars, in the spotlight.

After the Shelby AC Cobra was introduced in 1962, the first 75 examples used Ford’s 260 ci V-8 engine, which was soon replaced by the then-new 289 ci V-8. The Cobras took the U.S. Manufacturer’s Championship three years in a row—1963, 1964, and 1965—a stellar hat trick for a relatively new name in motorsport. In 1965, Shelby’s Daytona Coupe, a pure race car designed by Pete Brock to take on Ferrari’s 250 GTO, won the FIA International Championship for GT Manufacturers, making Shelby the first stateside constructor to win an international title. Ferrari, and the rest of the competitive field, would soon hear more when Ford enlisted the Texan and his star team, including Ken Miles, Phil Remington, and Pete Brock, to develop the GT40 in order to win the 24 Hours of Le Mans.

Meanwhile, it was time for a wilder AC Cobra, and in 1965, Shelby built a car around Ford’s big-block V-8. Development initially began with a new aluminum-block version of Ford’s 390 ci engine, but ultimately, the heavier 425 hp, cast-iron-block 427 ci side-oiler was used. As production continued through 1967, some Cobra 427s were fitted with the 360 hp 428 ci V-8 “Police Interceptor,” a lower-cost engine with a longer stroke and smaller bore. The mill was intended for road use instead of competition. Both engines were larger and more powerful than any 289, necessitating a complete redesign of the AC’s chassis and body.

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Preserving the original car’s 90-inch wheelbase, the 427 Cobra uses a massive 4-inch tube frame and a body that is 7 inches wider, obvious at first glance from the bulging front and rear fenders. The sophisticated coil-over suspension was designed by Ford engineers using the same computer dedicated to the GT40 race car. Ultimately, importing bodies and chassis from England was an unprofitable enterprise, and Shelby’s AC Cobra production came to an end after six years. Just over 300 Shelby 427 Cobras were built through 1967.

A brilliant example is a highlight of the upcoming RM Sotheby’s auction, returning to the Arizona Biltmore Resort & Spa on Thursday, January 25, 2024. Shelby chassis No. CSX 3237, built in March of 1966 and originally powered by a 428 ci V-8, rolled out of the Shelby factory finished in red with a black interior. According to the Shelby American Automobile Club (SAAC) Registry, the car’s provenance goes back to the first known owner, J. Rhoades Moore of Enid, Okla.

Like so many Cobras, it passed through a number of subsequent owners, receiving a full restoration in the 1990s by Cobra restorer Mike McCluskey. It was then sold to a new steward in Japan within the same decade, where it remained for a few years before returning to the U.S. Noted collector David Fonvielle acquired CSX 3237 in the mid-2010s, and commissioned a no-expense-spared restoration from Curt Vogt’s Cobra Automotive in Wallingford, Conn. All original components were rebuilt or upgraded, and a correct-spec 427 ci side-oiler engine was rebuilt for high-performance driving and touring, dyno-tested and delivering 460 brake horsepower at the crankshaft.

Acquired by the consignor in July of 2021, the car—finished in original colorways—retains original Sunburst wheels with Avon tires, as well as a number of correct accessories, including a convertible top with irons, side curtains, a tonneau cover, a reproduction of the owner’s manual, a jack, a grease gun, a can of paint, and a spare set of Halibrand-style wheels mounted with tires.

Significantly, a spare 428 ci Cobra Jet engine, the block for which has a date code that is correct for the 1966 Cobra’s model year, accompanies the car, which is estimated to fetch as much as $1.3 million.