This listing is for a New OBR Mercruiser Alpha I Upper Drive Shaft Assembly, which will fit models from 1969 to 1990 (Please note that Alpha I serial numbers are from OD494569 and before). New upper drives are assembled with a combination of all new OEM and new aftermarket parts using only high grade American steel for gears and shafts. This item is available in the following Gear Ratios: 1.50, 1.65, 1.84, and 1.98. When placing an order, please specify gear ratio. Please note that older "R" style 4 & 6 cylinder units require that you reuse your input shaft. Please use chart below to help identify your model:
Alpha I Standard Production Models
| ENGINE |
HP |
DISPLACEMENT
LITRE/CID
|
CYLINDERS |
GEAR RATIO |
TOOTH COUNT |
| 2.5 Litre |
120 |
2.5 / 153 |
4-In-Line |
1.98 |
20-24 |
| 3 Litre |
130 |
3.0 / 181 |
4-In-Line |
1.98 |
20-24 |
| 165 |
165 |
3.7 / 224 |
4-In-Line |
1.84 |
17-19 |
| 175 |
175 |
4.3 / 262 |
V-6 |
1.84 |
17-19 |
| 180, 470, 190 |
180 |
3.7 / 224 |
4-In-Line |
1.84 |
17-19 |
| 200 |
200 |
5.0 / 305 |
V-8 |
1.65 |
24-24 |
| 205 |
205 |
4.3 / 262 |
V-6 |
1.84 |
17-19 |
| 230 |
230 |
5.0 / 305 |
V-8 |
1.50 |
20-22 |
| 260 |
260 |
5.7 / 350 |
V-8 |
1.50 |
20-22 |
| 350 Magnum |
270 |
5.7 / 350 |
V-8 |
1.50 |
20-22 |
A Limited One-Year Warranty is included in the order. An additional Twelve-Month Extended Warranty is available. See options and pricing above. Please read the terms of OBR's New and Remanufactured Parts Warranty at https://obparts.com/obr-red-rhino-new-and-remanufactured-parts-warranty/.
