Lower unit Complete Replaces: Mercruiser® Alpha One Gen II series STD Rotation $795.00 Counter Rotation $995.00 Call toll free to order 888-567-8448 Lower unit Complete: Replaces: 1973-1991 Mercruiser® R/MR/Alpha One series. STD Rotation $695.00 Counter Rotation $895.00 Call toll free to order 888-567-8448 PRODUCT BREAKDOWN Lower Gears Water Pump Assembly Oil Seals and Gaskets Zinc Parts Bearings Bearing Carrier Shafts The prop and driveshafts are friction welded bimetal. The gearbox end of the shaft is comprised of hardened alloy 8620, while the shaft end exposed to the elements is 17-14PHSS