In June 1967, the model NSU TT superseded the Prinz 1000 TT, which had been in production since 1965. A new feature was the 1,200 cc engine with 65 hp. It was now equipped with two downdraught carburettors, an oil cooler and an overhead camshaft. That made the TT unrivalled as a sporty car for everyday use. For improved roadholding, the TT could be delivered with either 12" or 13" wheels.
Source: http://www.audi.com/me_partner/p_aeau000001/home/experience/audi_history/Evolution_of_the_models.html#source=http://www.audi.com/me_partner/p_aeau000001/home/experience/audi_history/Evolution_of_the_models/1945-1965/nsu_automobile/nsu_tt.html&container=layerModal
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