Mercruiser Sterndrive Gear Ratio Chart
Use this chart to determine your gear ratio before ordering a Mercruiser R-Style, Alpha 1 or Alpha 1 Gen 2 sterndrive.
| 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 |