Other than the special features previously mentioned, experimental components on this King of the Hill prototype include an 8,000-rpm tach and 17x9.5-inch-front and 17x11-inch-rear aluminum ZR1 prototype wheels fitted with Goodyear Gatorbacks with “not for sale” molded onto the inner sidewalls. The car was also fitted with a camouflage covering to hide the ZR1 tail panel. Those special tires are as rare as rare gets, but to make the car true to its original form, owner Brett Henderson had to try to find a set.
The car received an all-new bright-blue leather interior in 2017, though the original console plate, power key, and the 8,000rpm tachometer that was not available on production cars was retained.
“The car does have prototype rear Goodyear 315s. They are from the run of the 25 wide bodies built along with EX5023,” he said. “The dated rear wheels are from the same batch of 25 cars.” (The phrase “wide bodies” is in reference to the wider width of the rear body, one of the distinguishing features of the production ZR1. In all, 25 prototypes were built during July of 1987 for testing.) The original camo tail panel covering was gone, thus it had to be replicated.

Back from the grave

Henderson’s ZR1 prototype was one of what Corvette fans refer to as the “UK graveyard cars.” The ZR1 prototypes were destroyed in the U.K., or were supposed to be fully destroyed, per a GM edict issued in 1990. To the vast majority of people, Henderson’s test car seemed destroyed as per the GM requirement. Indeed, it was badly flattened through the use of a front-end loader, but the frame, suspension and most of the body tub remained largely intact. The majority of the fiberglass bodywork, as well as the windshield frame, were destroyed. However, the chassis and door geometry were not affected. At the time, it was sufficiently damaged to pass for destroyed. After all, no one would try to piece it back together, because it was cost prohibitive. Right? Wrong! As time passed, interest in the C4 generation of Corvettes began to increase. Though still not among the most coveted of Corvettes, there are some serious fans of the design. Furthermore, to some collectors, owning a prototype ZR1 has strong appeal, including to Henderson. He bought the car from Geoff Jeal, who was the chief calibration engineer for Lotus at the time the KOH project was in progress.
The dash came from a 1987 Corvette with the bright blue exterior and interior color scheme.
The other surviving prototype, EX-4607, was used to test all of the new-for-1988 features. This car was also driven extensively at the Milford Proving Grounds to test all the improvements to the C4 suspension, steering and brakes. Later, it was among the batch of Corvettes sent to England to assist in the development of the King of the Hill prototype. It was registered EX-4607 at the local vehicle licensing office as “E282 LAC” in January 1988. After its U.K. engineering assignment, it should have been returned to the United States or crushed in the United Kingdom, but it was eventually sold to a farmer in Essex in the early 1990s.

Henderson found many of the extremely rare replacement parts needed to bring his car back from the dead. Among them were two NOS pieces — the rear upper surround panel and the luggage compartment tub — plus three empty “birdcages” that were used by General Tire, of Marion, Ind., for panel fitment. (General Tire made panels for GM.) The three birdcage-frames were not stamped with a vehicle identification number. A number of pre-production ZR1 components were used to rebuild the car’s body.