The KJ 500 was built by Ken Kitchin and Roy N. Jones in the loft of St. Peters Street Garage in Cardiff in 1952. The frame was cut with a hacksaw from Reynolds tube, the joints filed to fit, and then welded up. The front suspension lower wishbones were hand-made from steel tubing, and that at the rear incorporated suspension links made from the tie rods from a Standard Vanguard. The leaf spring was locally made. The steering box came from a JBS 500, the inner ball joints were Morris Minor, and the front stub axles, knock-off hubs and wheels (re-rimmed and spoked by Dunlop) were salvaged from a MG T-series sports car. Dampers and brakes were by Girling, but the back brake plates were hand-made and the gearlever was made from a high tensile aluminium pushrod from a Prat and Whitney aircraft engine.
The 1.5 gallon tank was made from an aircraft hydraulic tank, feeding methanol by gravity to the 500cc JAP 4-stud engine. A four-speed Burman gearbox was mated to this, and after some experimentation a remote-needle Amal carburettor was used. Bodywork was made by Tom Harvey in aluminium and painted MG red.
The KJ 500 took about 18 months to complete, and upon being rolled out of the garage was immediately fired up and driven around the block. It was campaigned at various speed events and recorded a time of 49.53 seconds at Prescott, considered good for a first-timer. The hillclimb champion David Boshier-Jones tried it out and thought it compared well with other cars he had driven.