Proof of the operation upon any street or highway of North Carolina at a speed in excess of the limits provided by law of any motor vehicle when the motor, or any mechanical part or feature, or the design of the motor vehicle has been changed or altered so that there is a variation between such motor vehicle as changed or altered and the motor vehicle as constructed according to specification of the original motor vehicle manufacturer, with the result that the potential speed of such vehicle has been increased beyond that which existed prior to such change or alteration, or the proof of operation upon any street or highway of North Carolina at a speed in excess of the limits provided by law of any motor vehicle assembled from parts of two or more different makes of motor vehicles, whether or not any specially made or specially designed parts or appliances are included in the manufacture and assembly thereof, shall be prima facie evidence that such motor vehicle was operated at such time by the registered owner thereof. (1953, c. 1220.)