The 1.75 Right-Hand (RH) Gear Set Kit, Mercury Sportmaster and Torquemaster from Buckshot Racing #77 is a precision-engineered replacement for Mercury OEM part number 859321T04.
Designed for Mercury Racing 3.0L and 3.2L Sportmaster gearcases and Torquemaster lower units, this gear set delivers high durability, smooth mechanical power transfer, and consistent performance under extreme load and RPM conditions. It is specifically built to meet the needs of performance boating enthusiasts and professionals demanding reliable operation in high-stress marine environments.
Utilizing a 1.75:1 gear ratio, the 1.75 Right-Hand (RH) Gear Set Kit, Mercury Sportmaster and Torquemaster from Buckshot Racing #77 strikes the optimal balance between acceleration and top-end speed. This makes it especially well-suited for performance outboards where quick throttle response and precise handling are essential.
The gear ratio enhances thrust efficiency and delivers more consistent torque transfer across the full RPM range, ensuring responsive control during tight turns, race starts, and sustained high-speed runs.
Manufactured from heat-treated, high-strength alloy steel, the 1.75 Right-Hand (RH) Gear Set Kit, Mercury Sportmaster and Torquemaster from Buckshot Racing #77 is built to handle the mechanical demands of aggressive boating applications. The gears are CNC-machined to aerospace-grade tolerances for uniform meshing and long-term durability.
A micro-polished surface finish minimizes internal friction and reduces heat buildup during extended use, resulting in smoother performance, lower wear, and extended service intervals. These engineering features support reliable operation even in offshore, tournament, and high-output recreational boating.
As a direct replacement for Mercury OEM part 859321T04, the gear set kit requires no modification to the lower unit and installs cleanly into 3.0L and 3.2L Sportmaster or Torquemaster gearcases. The kit is designed for straightforward integration, though professional installation is recommended to ensure correct setup of gear lash, bearing preload, and shaft alignment. Please note that this kit does not include the prop shaft seals for 1.25-inch diameter shafts, which must be sourced separately depending on application.
This gear set kit is confirmed to fit a range of Mercury Racing outboard engines equipped with compatible gearcases. Supported models include the 225 HP Pro XS 6-cylinder (3.0L), 250 HP Pro XS 6-cylinder (3.0L), 250 HP XS 6-cylinder (3.0L), 250 HP Sport XS 6-cylinder (3.0L), 300 HP XS 6-cylinder (3.2L), and the 300X EFI PRO MAX 3.0L.
These engines are typically paired with either Sportmaster or Torquemaster lower units and benefit from the precision, durability, and performance improvements offered by this gear set.
The 1.75 Right-Hand (RH) Gear Set Kit, Mercury Sportmaster and Torquemaster from Buckshot Racing #77 is the result of extensive testing and real-world performance validation. Its enhanced material strength, precision machining, and thermal efficiency characteristics make it a preferred solution for rebuilding high-performance Mercury Racing gearcases.
Whether restoring worn internals or upgrading to handle more aggressive loads, this kit provides a robust and reliable foundation for high-speed marine performance.
For technical support, installation guidance, or ordering inquiries, contact Mike Hill at +1-714-697-1716 or via email at mike@buckshotracing77.com.