Cobra SX Engine Coupler | Sierra 18-21752-1 Coupler connects OMC & Volvo Penta GM V6 & V8 engines to stern drives. Fits OMC and Volvo 4.3L V6 engines from 1986 to present Fits OMC and Volvo 5.0L engines from 1986 to1988 and 1998 to present Fits OMC and Volvo 5.7L engines from 1986 to1992, 1994, 1996 to present Replaces OMC 984290, 986120, 3853917, and 3858437 Replaces Volvo Penta 3853917 and 3858437 Replaces Sierra 18-21752