Mercury/Mariner, 25-70HP - 3 1/4 Gearcase - 13 tooth spline, 25HP Bigfoot (4-Stroke) 1999-2005, 30HP Bigfoot (4-Stroke) 2010-, 30HP (2&4-Stroke) 1994-2005, 30HP Sea Pro/Marathon 1994-, 35HP 1984-89, 402&500 Models 1974-84, 40HP (2&4-Stroke/not bigfoot) 1977-, 40HP Sea Pro/Marathon 1977-, 45HP 1986-89, 48HP Mariner, 50HP (2&4-Stroke/not bigfoot) 1977-, 55HP Mercury/Sea Pro/Marathon) 1995-, 60HP (4-Stroke, not bigfoot or Sea Pro/Marathon) 1978-, 60HP (2-Stroke) 1978-, 70HP (Model 700) 1983, 70HP 1991-95, 75HP 1996-98, Force 40/50HP 1995-98