Bill Thomas had become pretty successful modifying various Chevrolet products for track use. After some success racing Corvettes in the late 50s, in 1960, he went on to start his own company that turned Chevy IIs and Corvairs into viable track cars. He became so good at it, that by 1963, he had the attention of Vince Piggins, then-head of the GM Performance Product Group. Piggins asked Thomas to develop a concept car utilizing GM Performance parts.
Thomas quickly acquired a 327 ci Corvette engine, a Muncie transmission, and the gear to assemble an independent rear suspension. Other parts such as spindles and brakes were also pulled directly from the GM Performance parts bins. Thomas relied heavily on his lead fabricator Don Edmonds to design and build the chassisfor the project. Edmonds developed most of his cars with very little in the way of formal drawings. The project, ultimately named the Cheetah, was no different. Edmonds laid the components out on the shop floor and chalked out the basic chassis outline. Even later in development, there were very few control drawings for the Cheetah, and those that existed only had some cursory dimensions on them.
Once the chassis was defined, the work of creating the body began. Edmonds built a plywood buck that was sent off to have body molds made. Once they built the first fiberglass body from which to build the molds, they built a second one - this time out of aluminum. That aluminum version was the only one made of the material, and it was sold to GM for evaluation purposes.
The original intent of the Cheetah concept was to create a car that could be driven to local hangouts and cruise-ins, with the intent of showing off the GM Performance parts. With that primary application in mind, the chassis and body designs were built more for show than go. With it’s curvaceous lines, extreme proportions, and gullwing doors, the Cheetah drew a lot of attention for it's appearance. It was only later when they experienced the car’s brutal acceleration capability that they considered they might want to race it.
The Cheetah’s layout was very interesting. The DOM (drawn-over-mandrel) chromoly tube frame housed the engine in the front, sort of. The engine was so centered in the chassis behind the front wheels that there was literally no driveshaft. The transmission connected to the rear differential with nothing more than a universal joint. The weight distribution was essentially the same as rear mid-mounted engined cars, and without the need for a transaxle. This peculiar set-up put the driver’s legs beside the engine. The footwells even needed curved sections over the driver and passenger legs just to make room for the headers. This made for a very hot driver’s compartment - an attribute element that would be problematic when the Cheetah would go racing.
In 1964, The Cheetah was campaigned in various series of races. The original plan was to have the Cheetah driven principally by Dave MacDonald - a former driver of Bill Thomas's Corvettes, but Carroll Shelby offered him a seat in one of his new Cobras, and MacDonald accepted the offer. Jerry Titus and Ralph Salyer both campaigned the Cheetah, with Salyer winning 11 events with the car through 1964 and 1965. Despite Salyer’s success, the car’s original lack of planning for racing was becoming problematic. Salyer’s car ultimately became the only ‘official’ Cheetah roadster, after the top was cut off as a coping mechanism to dissipate the extreme heat in the passenger compartment. Furthermore, the engine was also regularly overheating in race conditions. Over time, a series of different options were pursued to keep the engine cool, including various hood cutouts and spoilers. Ultimately that issue was resolved with a substantially larger radiator. Another major issue was the chassis. Not having been designed for track duty, it lacked any significant triangulation to be rigid enough for the loads of road racing. The Cheetah was known to be so flexible that the suspension geometry was continuously changing during a race, just based on the flex of the chassis.
The exceededingly poor handling was often more than compensated for with power. The racing Cheetahs were motivated by Bill Thomas’s 377 ci fuel injected small block V8s, and in a car weighing in at around 1500 pounds. There were few cars that could touch it in a straight line. There are several times it posted after 1/4 mile times than 427 Cobras at the drag strip.
The Cheetah project ultimately fell victim to two cruel fates. Thomas's shop suffered a devastating fire, and as if that weren't enough, GM instituted their internal ban on racing support. The ban quickly evaporated Thomas’s access to the quantity of performance parts needed to build the 1000 chassis needed for homologation. It’s a shame that Thomas wasn’t able to see through to his original intention, which was to address all the known issues of the Cheetah with the Super Cheetah - a more comfortable car with more interior space, a longer wheelbase, and with a more aero body suitable for Le Mans-grade speeds. The Super Cheetah was planned to be four inches wider and 19 inches longer than the original.
At the end of the day, the Cheetah was never a project picked up by General Motors. While they may have vicariously supported the effort, the cars were always the intellectual property of Bill Thomas. The exact number of original Cheetahs built is unclear, but based on the number of fiberglass bodies built by the supplier, it is believed to be 23 or less. Later, there were various attempts to build continuation versions of the Cheetah, which were even more wicked than the original.
As highly uncommon and desirable it is to see an original Shelby Cobra in person, seeing a Cheetah first hand is in a whole other league of rarity.