MerCruiser Alpha Gear Tooth Ratio Chart

By June 17, 2019 Outdrive

Mercruiser R-Style Sterndrives (1969 – 1983)

Engine HP Liters/CID Cylinders Gear Ratio Tooth Count Year
2.5 Liter 120 2.5/153 4 1.98 20-24 1969-1983
2.5 Liter 130 2.5/153 4 1.98 20-24 1969-1983
165 165 3.7/224 6 1.65 24-24 1969-1983
470 170 – 190 4.3/262 4 1.84 17-19 1969-1983
215 – 233 205 – 230 351 8 1.5 20-22 1969-1983
260 260 5.7/350 8 1.5 20-22 1969-1983

Mercruiser Alpha 1 (1984 – 1990 Models)

Engine HP Liters/CID Cylinders Gear Ratio Tooth Count Year
2.5 Liter 120 2.5/153 4 1.98 20-24 1984-1990
3 Liter 130 3.0/181 4 1.98 20-24 1984-1990
165 165 3.7/224 4 1.84 17-19 1984-1990
175 175 4.3/262 6 1.84 17-19 1984-1990
180, 190, 470 180 3.7/224 4 1.84 17-19 1984-1990
200 200 5.0/305 8 1.65 24-24 1984-1990
205 205 4.3/262 6 1.84 17-19 1984-1990
230 230 5.0/305 8 1.5 20-22 1984-1990
260 260 5.7/350 8 1.5 20-22 1984-1990
350 Magnum 270 5.7/350 8 1.5 20-22 1984-1990

Mercruiser Alpha 1 Gen 2 (1991 & Newer)

Engine HP Liters/CID Cylinders Gear Ratio Tooth Count Year
3 Liter 130 3.0/181 4 2.0 24-24 1998-2005
3 Liter 130 3.0/181 4 1.94 20-24 1991-2005
4.3 Liter 175 4.3/262 6 1.81 17-19 1991-2005
5.0 Liter 230 5.0/305 8 1.61 24-24 1991-2005
5.7 Liter 260 5.7/350 8 1.47 20-22 1991-2005