This SEI Marine Upper Gear Set is engineered as a direct replacement for MerCruiser Type I, R, MR, and Alpha One sterndrives from 1972–1990, designed specifically for 5.7L V8 engines.
Featuring a 1.47 / 1.50 gear ratio, this precision-machined gear set ensures optimal performance, torque balance, and smooth power delivery.
It replaces OEM 43-18410A4 and is also compatible with Gen II drives (Serial #0L000039 and below).
Manufactured from high-strength, marine-grade materials, this SEI gear set offers OEM fit and long-term reliability, backed by SEI’s 3-Year Fault-Free Warranty.
Product Features
- Direct OEM Replacement: Replaces MerCruiser OE# 43-18410A4
- Fitment: MerCruiser Type I, R, MR, and Alpha One drives (1973 and newer)
- Additional Fitment: Gen II drives (Serial #0L000039 and below)
- Engine Compatibility: 5.7L V8 models
- Gear Ratio: 1.47 / 1.50
- Condition: 100% brand-new SEI Marine replacement gear set
- Warranty: 3-Year Fault-Free Warranty provided by SEI Marine
Additional Information
Note: Designed for 5.7L V8-powered MerCruiser Alpha One and compatible Gen II applications.
If you require matching lower unit components or additional gear hardware, please email or fill out the contact form and we’ll assist you in finding the correct parts.
Shipping Information
SHIPPING: Additional shipping fees to Alaska, Hawaii, U.S. Territories, or international destinations will be calculated after checkout.
You will receive an email and a PayPal money request for the additional shipping charges at the email address provided.
(Some items are excluded from international shipping.)
Customer Support
For questions or to confirm compatibility, please email customerservice@marinepartswarehouse.com .
Please include your engine model number to help confirm proper fitment before ordering.
