MerCruiser 43-55778A3 120hp 140hp Upper Pre/R/MR/Alpha One 1.98 Gearset Gearcase
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- All 120hp 2.5L & 140hp 3.0L 4cyl applications for Pre-Alpha/R/MR/ALPHA ONE Gen 1, so 1970-1990 as a general rule.
- (You may need to replace the bearing on top of the shaft depending on whether you have a 1970-1982 vs 1982 & Up application as they each used different bearing sizes)
- (Actually these were also used on Gen II drives 1991-1997)
- The gear set here is MerCruiser 43-55766 / 43-55778 > 43-55778A3 (Also Equivalent to 43-55766A2 / 43-55766A3 / Sierra 18-2205)
- 20-24 (tooth count) 1.98 Ratio for 4-cylinder GM Chevy 120hp 2.5L 153CID / 140hp 3.0L 4cyl 181CID sterndrive engines.
- Also Included is upper driveshaft assembly 45-55797
- If you have any questions on compatibility, or any other questions about this item, please don't hesitate to contact me.
- The existing bearings are probably fine, but please inspect bearings beforehand to make sure they are to your liking as your races may be different than the bearings here, its always recommended to start with fresh bearings & races when performing this type of service work, but this is ultimately up to your discretion.
- Freshwater Used Parts.
- These look great and were removed from a completely functional upper gearcase.
- Purchase with confidence!
1970 1971 1972 1973 1974 1975 1976 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990