The Mk III was a road-car only, of which seven were built.
The car had four headlamps, the rear part of the body was expanded to make room for luggage, the 4.7-liter engine was detuned to 228 kW (306 hp; 310 PS), the shock absorbers were softened, the shift lever was moved to the center, an ashtray was added, and the car was available with the steering wheel on the left side of the car.
As the Mk III looked significantly different from the racing models many customers interested in buying a GT40 for road use chose to buy a Mk I that was available from Wyer Ltd. Of the seven MK III that were produced four were left-hand drive.