Beginning in April 1968, Ford began factory installing a version of the 428 engine known as the "Cobra Jet". The GT500 was subsequently known as the Shelby Cobra GT500 KR. The initials KR stood for "King of the Road." Ford rated the Cobra jet at 335 hp but with 440 lb⋅ft of torque at 3,400 rpm, the horsepower was considered significantly underreported, as it was later found that the car made closer to 435 hp. Shelby's KR engine was left stock adding die-cast aluminum valve covers with "Cobra Lemans" to note Ford's FE engine family victory over Ferrari at Le Mans in 1966 and 1967.

This gorgeous KR, wearing Shelby No. 04110, paired the original matching-numbers 428 Cobra Jet with C-6 Select-O-Matic 3-speed automatic transmission, its shift lever coming out of the floor through a new-for-1968 Shelby-unique center console & ice cold factory air conditioning. The black deluxe bucket-seat interior is surrounded by tinted glass, Shelby’s autograph adorns the glove box door, and a Philco pushbutton AM radio and tilt steering column are among the other interior amenities. Outside, the Highland Green paint is accented with white rocker panel stripes, and Lucas driving lights are mounted in the grille. This car’s double A-arm front suspension has been rebuilt, and the chassis is equipped with power steering and power brakes.

The KR rolls on Goodyear/Shelby Speedway 350 bias-ply tires and Shelby’s optional 10-spoke aluminum wheels. The history of this Shelby GT500KR is well- documented in the Shelby Registry (SAAC).

While Ford rated the 428 Cobra Jet at 335 HP, less than the 360 HP rating given the 428 Police Interceptor it was replacing in the Shelbys, its true output was believed to be closer to 400 HP. Its 440 lb-ft torque peak also surpassed the Police Interceptor’s 420. All the Cobra Jets in Shelby GT500s were fitted with ram air induction, which meant the distinctive oblong Cobra air cleaner housings gave way to more conventional round air cleaners with rubber gaskets that sealed to the underside of the Shelby’s dual-scooped fiberglass hood.