Sierra 18-3577-2 Big Block Water Circulating Pump for Mercruiser, Volvo, OMC For Big block GM engines with stamped steel timing covers Bi-Directional Used on Mercruiser, Crusader, OMC, Pleasurecraft and Volvo Penta Marine engines. ss from 18-3577-1 Interchangeable with Crusader 17670 30109 67859 811573 EMP 95-01660 GM 6269358 Mercruiser Stern Drive 17670 46-8M0113735 49139 54534 59972 67859 811573 850454 850454002 8504541 878342 F6269358 FI1100997 FI1101053 MES WP415M OMC Inboard 6269358 OMC Ste