top of page

The Buckshot Racing #77 1.75 Right-Hand (RH) Gear Set Kits are engineered to replace Mercury OEM Part Number 859321T04. Designed for Mercury Racing 3.0L Sportmaster Gearcases and Torquemaster Lower Units, this gear set delivers durability, smoother power transfer, and consistent high-speed performance under the most demanding conditions.

 

Whether you’re pushing the limits or fine-tuning for recreational performance, our gear set kits offers proven reliability and precision engineering that elevates your boating experience.

 

Key Features and Specifications

SpecificationDetails
Gear Ratio1.75:1
CompatibilityMercury Racing 3.0L Sportmaster Gearcases & Torquemaster Lower Units
Replacement for OEM Part859321T04
RotationRight-Hand (RH)
MaterialHeat-treated, high-strength steel
Precision ManufacturingAerospace-grade CNC machining
Surface FinishMicro-polished for reduced friction
DurabilityEngineered for high torque and RPM

 

  • Optimized 1.75:1 Gear Ratio
    The 1.75:1 ratio strikes the perfect balance between top-end speed and acceleration, making it ideal for high-performance Mercury Racing 3.0L Sportmaster gearcases and Torquemaster lower units. This gear set enhances thrust efficiency, ensuring maximum power delivery for high-speed runs and tight control.

 

  • Built for Durability and High-Torque Conditions
    Made from heat-treated, high-strength steel, the Buckshot Racing #77 gear set withstands extreme torque and RPM conditions common in performance boating and offshore racing. Our precision manufacturing process ensures tight tolerances for enhanced durability and a perfect fit.

 

  • Reduced Friction and Heat Build-Up
    The gears feature a micro-polished surface finish to minimize friction and reduce heat generation. This translates into longer gear life, smoother operation, and reliable performance during extended high-speed use.

 

  • Direct Replacement for Mercury OEM Part 859321T04
    This kit is a direct-fit replacement for Mercury OEM 859321T04, ensuring seamless integration with your 3.0L Sportmaster or Torquemaster gearcase. No modifications are required, making installation straightforward and hassle-free.

 

  • Proven High-Performance Engineering
    Rigorous real-world and simulated testing ensures the Buckshot Racing #77 gear set delivers consistent performance under race-level stress. It provides tighter, more reliable power transfer, critical for maintaining control at high speeds or during aggressive maneuvers.

 

Applications

The 1.75 RH Gear Set Kit is ideal for:

  • High-Performance Boating: Rebuild your Mercury Racing 3.0L gearcases. Designed to handle high-torque, high-RPM environments with precision.
  • Recreational Performance Boating: Improve acceleration and top-end performance with unmatched reliability.

 

Installation and Fitment

 

The Buckshot Racing #77 1.75 RH Gear Set Kit is a direct replacement for Mercury OEM Part 859321T04. It is fully compatible with:

 

  • Mercury Racing 3.0L and 3.2L Sportmaster Gearcases
  • Mercury 3.0 Liter Torquemaster Lower Units

 

Professional installation is recommended to ensure proper fitment and alignment for optimal performance.

 

The Buckshot Racing #77 1.75 Right-Hand Gear Set Kit is engineered to meet the demands of high-performance boating, providing exceptional durability, precision, and efficiency.

 

Replacingyour  Mercury OEM Part 859321T04, this gear solution for Mercury Racing 3.0 Liter and 3.2 Liter XS Sportmaster gearcases and Torquemaster lower units with 1 1/4 inch prop shaft will get you running strong on the water again.

 

Contact Mike Hill with any questions at +1-714-697-1716 or mike@buckshotracing77.com

1.75 RH Gear Set Kit, Mercury 3.0 Sportmaster

SKU: 859321-77
$695.00Price
    bottom of page