Initial series production engines (Mk.II, Mk.V, Mk.VIII, and Mk.XIV) were sold to Lotus exclusively, and many of the other racing engines up to Mk.XII were delivered to Team Lotus. The success of Formula Junior engines (Mk.III, IV, XI, and XVII) started bringing in non-Lotus revenues, and the establishment of Formula B by the Sports Car Club of America (SCCA) allowed the financial foundation of Cosworth to be secured by the increased sales of Mk.XIII, a pure racing engine based on Lotus TwinCam, through its domination of the class. This newly found security enabled the company to distance itself from the Lotus Mk.VII and Elan optional road engine assembly business, and allowed its resources to be concentrated on racing engine development.