Rubuta ci gaba ga wannan sakin layi - FIA ta zartar daga 1966, sabbin ka'idojin injin 3-lita zasu fara aiki. Lotus ba su da gasa sosai. Farawa tare da injin Coventry-Climax na lita 2 a cikin Lotus 33, Clark bai sami maki ba har zuwa Babban Prix na Burtaniya
da kuma na uku a Grand Prix na Dutch na gaba. Daga Grand Prix na Italiya zuwa gaba, Lotus ya yi amfani da injin BRM H16 mai matukar rikitarwa a cikin motar Lotus 43, wanda Clark ya lashe Grand Prix na Amurka. Ya kuma ɗauki wani wuri na biyu a Indianapolis 500, wannan lokacin a bayan Graham Hill.