The Super Air Nautique S21 comes standard equipped with the PCM ZR4, and has a wide array of additional engine options. Step up to the optional PCM and GM Marine direct-injection engines that provide industry-leading power in both the 5.3L PCM ZZ5 and the 6.2L PCM ZZ6. If you’re looking for even more power, the S21 has three other engine options: the 7.4L naturally-aspirated PCM ZR7, the Yanmar 8LV Diesel engine that delivers 595 ft-lbs. of torque, or the most powerful engine in the industry, the PCM ZZ8, that provides 600 horsepower and 608 ft-lbs. of torque!