The Buckshot Racing #77 twenty-four (24) piece 12" Studs-Down Stud Kit is a high-strength, race-grade hardware solution engineered for compatibility with Mercury Racing midsections originally found on F1, F1H20, SST-120, S3000, APX 200, 250, and 360 APEX race outboards.
Stud options: This kit is available with your choice of stud material to match your build goals:
ARP Kit: eight (8) ARP broached Allen key studs manufactured from 8740 chrome moly steel.
Mercury OEM Kit: eight (8) stainless steel studs for customers who prefer an OEM-style stainless option with enhanced corrosion resistance for harsh freshwater or saltwater use.
It is designed to replace legacy and modern Mercury OEM hardware, including part numbers 822118, 12-35935, 859116, 822836, and 34933.
This kit serves as a direct, high-performance replacement for original fasteners used in Mercury Racing Super Speedmaster 4 (SSM #4 / Mark 4), later-style Super Speedmaster 6 (SSM #6 / Mark 6), and earlier Studs-Down midsection configurations.
The stud kit is compatible with Baicour DM 12-inch Replacement Exhaust Housings, the Mercury Racing smooth back 12-inch midsection (OEM #821986A5), the APX driveshaft housing (OEM #8M0176557), and the Mercury gearbox housing (OEM #8M0176563).
These components are standard across a broad spectrum of Mercury Racing competition outboards, including Tunnel Hulls, Outboard Drag boats, Champ, F1, SST-140, SST-120, SST-200 (200 XS Optimax with 12-inch midsection), S2000, S3000, and APX platforms such as the APX 200, APX 250, and APX 360 competition outboard.
Standard ARP stud construction (if selected): The eight (8) ARP broached Allen key studs are manufactured from 8740 chrome moly steel, offering tensile strength in the 180,000–210,000 psi range. These studs provide superior clamping force and fatigue resistance under the extreme mechanical loads typical in high-speed marine racing.
The broached Allen head facilitates precise installation and removal, reducing the chance of thread damage—ideal for frequent lower unit servicing.
Also included are eight (8) extra-thick, case-hardened stainless steel washers. These are designed to distribute loads more evenly, reduce distortion of mating surfaces, and resist deformation, corrosion, and fatigue—ensuring long-term performance in aggressive freshwater or saltwater environments.
The eight (8) stainless steel 7/16"-20 Nylock fine thread nuts feature integrated nylon locking inserts for vibration resistance and secure clamping in high-performance marine applications. The fine threading enhances torque precision and holding strength, which is critical for maintaining gearcase and midsection alignment under load.
Care recommendations:
For ARP 8740 chromoly studs: clean after use and apply a light coating of high-quality motor oil or a corrosion-inhibiting lubricant such as WD-40. Store in a dry environment and reapply lubricant periodically for maximum corrosion protection.
For Mercury OEM-pattern stainless studs: rinse, clean, and use a light corrosion inhibitor as needed for your environment, especially after saltwater exposure.
Contact Mike Hill at +1-714-697-1716 or email mike@buckshotracing77.com for technical support.