The 6-Piece Buckshot Racing #77 ROS Drivershaft Housing Stud Kit is a heavy-duty hardware upgrade designed for Mercury Racing and Mercury Marine 2.5-liter V6 outboards.
This kit replaces the factory Mercury OEM drivershaft housing stud 818908, along with the Mercury stainless steel washer 816056 and Mercury stainless Nylock nut 82670817 used to secure the driveshaft housing (midsection) to the powerhead adapter plate.
For high-performance engines used in offshore and racing environments, upgrading these fasteners during maintenance or engine assembly provides improved clamping strength, easier installation, and long-term reliability.
ARP 8740 Stud Construction for High-Performance Engines
At the center of this kit are ARP 8740 chromoly steel studs, a material widely used in high-performance racing engines due to its superior tensile strength and fatigue resistance. Compared with standard factory studs, ARP 8740 provides significantly greater strength, helping the fasteners withstand the vibration, heat cycles, and mechanical loads commonly experienced by high-RPM Mercury V6 two-stroke engines.
While ARP 8740 offers exceptional strength, it can be slightly less corrosion resistant than stainless steel in marine environments. To balance durability and corrosion protection, Buckshot Racing #77 recommends using 2-4-C Grease on the studs along with our OEM-style stainless steel washers and stainless Nylock lock nuts, providing reliable clamping while maintaining corrosion resistance around the exposed hardware.
Each stud also incorporates a 5/32-inch broached Allen installation socket, allowing technicians to thread the studs into the adapter plate cleanly and accurately. This design eliminates the need for the traditional double-nut installation method and helps prevent thread damage during engine assembly.
Complete Hardware Set Included
The Buckshot Racing #77 ROS Drivershaft Housing Stud Kit includes the complete hardware needed for this location on the engine. The kit contains two (2) ARP 8740 drivershaft housing studs replacing Mercury OEM part number 818908, two (2) stainless steel washers corresponding to Mercury part number 816056, and two (2) stainless Nylock lock nuts corresponding to Mercury part number 82670817.
This configuration mirrors the original Mercury hardware layout while upgrading the studs to ARP racing-grade fasteners for improved strength and serviceability.
Compatible Mercury Racing and 2.5L V6 Outboards
This stud kit fits many Mercury Racing and Mercury Marine 2.5-liter V6 engines, including several of the most recognized high-performance models used in racing and performance boating.
Common applications include the Mercury Racing 260 EFI, 280 ROS (Race Offshore), and 300 Drag, as well as 200 EFI Pro Max, 225 EFI Pro Max, and 150/200 Pro Max Super Mag engines. It also supports various 2.5L EFI Offshore and EFI performance models, along with 200 HP 2.5-liter V6 outboards commonly used on bass boats and performance hulls.
These engines appear in a wide range of boating environments, including high-performance bass boats, offshore performance hulls, and racing applications, where secure powerhead mounting hardware is essential.
The broached Allen socket simplifies installation and removal of the studs, while the stainless Nylock lock nuts ensure the fasteners remain secure under the vibration and load typical of high-performance outboards.
Designed for Mercury Racing Performance Builds
Engines such as the Mercury Racing 260 EFI, 280 ROS, and 300 Drag are often operated at high RPM and under demanding loads, which places additional stress on the powerhead mounting hardware. Upgrading to ARP 8740 drivershaft housing studs helps ensure the connection between the powerhead, adapter plate, and midsection remains secure.
For owners rebuilding or servicing Mercury 2.5-liter V6 performance engines, the Buckshot Racing #77 ROS Drivershaft Housing Stud Kit provides a stronger and easier-to-install replacement for factory hardware.
Contact Mike at 714-697-1716 or mike@buckshotracing77.com for technical support.