1968 Shelby Mustang GT500KR: 428 Cobra Jet and Four-Speed Manual

The 1968 Shelby Mustang GT500KR’s appeal starts with a rare combination: a 428-cubic-inch Cobra Jet V8, a four-speed manual and the Shelby details that set it apart from a standard Mustang. This Acapulco Blue fastback is an original example, built on July 16, 1968, and is now offered with documentation covering its build and ownership.

Big-block power, with a manual gearbox

The “KR” stands for “King of the Road.” Shelby used the name for its most powerful Mustang offered to the public at the time, basing the car on the GT500 and installing Ford’s 428-cubic-inch (7.0-liter) FE Cobra Jet V8. For drivers drawn to the era’s high-output muscle cars, the four-speed manual in this example is a key part of the package: it puts gear selection in the driver’s hands and suits the car’s straight-line character.

The factory specification lists the Cobra Jet at 335 bhp and 440 lb-ft of torque. Accounts of the model have suggested that the horsepower figure understated the engine’s output, with a figure of 435 bhp later attributed to it. That higher number is not the rating on the factory specification sheet, so the distinction matters when comparing period claims with the documented rating.

The engine used high-flow cylinder heads and a pair of 600-cfm Holley carburetors. Die-cast aluminum valve covers carried “Cobra LeMans” lettering, a reference to Ford V8s used in the GT40’s back-to-back wins at the 24 Hours of Le Mans in 1966 and 1967. The combination gave the KR its imposing reputation in a straight line. The weight of the big-block engine over the front axle, though, made it less suited to tight corners than the lighter Shelby GT350.

Chassis and body changes

Shelby added hardware intended to help the GT500KR manage its power. The package included heavy-duty suspension, a front strut brace, a roll bar, power steering and power-assisted front disc brakes, paired with wider rear drums. Inside, the driver faced an 8,000-rpm tachometer and a speedometer marked to 140 mph.

Fiberglass panels helped distinguish the Shelby from the regular 1968 Mustang. The GT500KR’s fiberglass parts included the nose section, hood, rear taillight panel, deck lid, quarter-panel extensions and side scoops. These changes gave the car a broader visual identity while reducing weight in some areas. Taken together, the equipment reflects a car developed around forceful acceleration, with the handling trade-offs that came with a large V8 up front.

Shelby built the GT500KR for the 1968 model year only. Production totaled 1,570 cars: 1,053 fastbacks and 517 convertibles. The limited run, Cobra Jet engine and distinct bodywork have made the model a sought-after Shelby. The source describes strong examples as typically selling for well into six figures, though it gives no asking price for this particular car.

This Acapulco Blue fastback

Built on July 16 and delivered new to Johnny Bolton Ford in Maitland, Florida, this car is one of the 1,053 fastbacks produced. It is also one of 530 GT500KRs finished in Acapulco Blue. Its equipment includes the GT Equipment and Decor Groups, functional hood scoops, a rear spoiler, air conditioning, a tilt-away steering wheel, AM/FM radio and a folding Sport Deck rear seat.

The cabin has black vinyl upholstery, front shoulder harnesses, auxiliary Stewart-Warner gauges and simulated woodgrain trim. The car also has 15-inch Magstar-style wheels. The odometer shows 20,000 miles; the current owner bought it in 2020 and has added about 500 miles since then. That limited recent use makes the maintenance history useful context for anyone assessing the car.

Work in 2022 included rebuilding the Holley carburetor and replacing the alternator, voltage regulator, ignition points and condenser. A Flowmaster dual exhaust system with quad tips was installed. The brake booster and tires were replaced around two years ago, and the power-steering hoses were renewed in May 2022.

Records and sale details

The sale includes a Deluxe Marti Report confirming the July 1968 build date, a factory specification sheet, the owner’s manual, service records and delivery documents. The car is titled in Arizona under the serial number shown on its Shelby American identification plate. Those records, along with its original configuration and four-speed gearbox, give prospective buyers concrete details to weigh alongside condition and inspection findings. The listing has further details and bidding information.

The Shelby GT500KR combined the GT500’s big-block foundation with the Cobra Jet engine and Shelby-specific equipment. This fastback’s documented build, Acapulco Blue finish and manual transmission make it a particularly clear example of that formula; its condition and recent mechanical work will be central to any buyer’s assessment.