 Total production of the engine was approximately 34,000 units, in 24 different varieties.Chapman named the engine the "Lotus Twin-Cam" at its introduction in 1962 and Lotus continued to use that name.When production switched from the Cortina-Lotus to the Ford Cortina Mark II-based Cortina Twin Cam in 1967, Ford began to call the engine the "Lotus-Ford Twin Cam".