This was about the last use of the 161 cubic inch 6 (in the Darrin). After limited use in 1955, the 161 was moved to industrial only. The engines offered in Jeep products were the 134 cu in 4 (F-head in some products, L-head in others) and the 226 K-F engine until they upgraded the 226 to overhead valves and overhead cap (the Tornado 230 cu in motor) around 1960.