The Buckshot Racing #77 6.75-inch Titanium Powerhead Stud is a premium replacement and performance upgrade for the long powerhead mounting stud used on many Mercury Marine, Mariner, and Mercury Racing V6 2-stroke outboards.
It cross-references Mercury OEM part numbers 78438, 784384, 784385, and 8M0034454 and is intended for applicable stock-style powerhead and midsection installations.
Mercury originally cataloged 784385 as a 3/8-16 / 3/8-24 powerhead stud, with the OEM dimensions. Mercury later superseded 784385 with 8M0034454, while 78438 and 784384 are earlier numbers in the same part-number family.
The Buckshot Racing #77 version is the nominal 6.75-inch titanium replacement used in our high-performance powerhead stud system.
It upgrades conventional steel hardware with Ti-6Al-4V titanium, a broached Allen-key installation feature, and a PVD coating for improved corrosion resistance, serviceability, and appearance.
Mercury V6 2-Stroke Powerhead Stud Fitment
This long powerhead stud fits many Mercury V6 2-stroke applications, including 135 HP, 150 HP, 175 HP and 200 HP Mercury outboards, as well as applicable XR2, XR4, XR6, XRi and Pro Max engines.
Buckshot Racing #77 offers this stud for many Mercury 2.0-liter, 2.4-liter, and 2.5-liter V6 2-stroke engines, including 150 HP, 175 HP, 200 HP, and 225 Pro Max applications using the corresponding long-stud location.
Applicable Mercury engines may include models such as V-135, V-150, V-175, V-200, XR6, 200XS DFI, 225X EFI Pro Max, 150 Pro XS and 175 Pro XS, depending on year, serial number, and midsection configuration.
Because Mercury used different stud lengths and combinations over many years, always verify the existing stud location and OEM part number before ordering, especially on modified race, offshore, or mixed-component engines.
Cross-Reference Part Numbers Mercury OEM: 78438, 784384, 784385, and 8M0034454, These numbers reference the same general long powerhead stud application through Mercury’s supersession history.
Ti-6Al-4V Titanium Construction
The Buckshot Racing #77 stud is manufactured from Ti-6Al-4V titanium, a high-strength alloy known for its excellent strength-to-weight ratio and corrosion resistance.
Powerhead mounting hardware is continually exposed to moisture, heat, vibration, and repeated service. Titanium helps eliminate much of the rust and corrosion commonly found on aging steel studs while maintaining the strength required for high-performance outboard use.
This makes the titanium stud well suited for Mercury performance bass boats, tunnel boats, drag boats, lake racers and restored V6 outboards where durability and future serviceability matter.
Broached Allen-Key Installation
One of the most useful features of the Buckshot Racing #77 titanium stud is the broached 5/32-inch Allen-key end.
Conventional powerhead studs can be difficult to remove or install after years of corrosion and heat cycling. The broached end gives the technician a positive way to turn the stud with a standard Allen wrench.
This eliminates the need to grip the threads with pliers or repeatedly double-nut the stud simply to install or remove it. The feature is especially useful during frequent teardown and rebuilding of Mercury Racing and high-performance 2.0L, 2.4L and 2.5L V6 engines.
PVD-Coated Titanium
Each Buckshot Racing #77 titanium powerhead stud receives a PVD — Physical Vapor Deposition — coating.
The coating adds a thin, hard surface layer that improves wear resistance and provides an additional barrier against corrosion while retaining the lightweight properties of the titanium base material.
The combination of Ti-6Al-4V titanium, PVD coating and a broached installation end creates a purpose-built fastener for performance marine applications.
Installation and Service
Before installing a new powerhead stud, inspect and clean the threaded hole in the block. Corrosion, old thread compound or damaged threads can prevent proper installation.
The Allen broach is intended primarily as an installation and removal aid. Do not use it to excessively tighten the stud into the block. Final powerhead clamping is created by the retaining hardware once the powerhead is installed.
Always follow the applicable Mercury Marine or Mercury Racing service procedure and torque specifications for the exact engine and midsection being assembled.
When replacing heavily corroded hardware, inspect the remaining studs, nuts and washers at the same time.
Buckshot Racing #77 Titanium Powerhead Stud
The Buckshot Racing #77 6.75-inch Titanium Powerhead Stud provides a corrosion-resistant, service-friendly upgrade for the original long Mercury powerhead stud used across many legendary 2.0L, 2.4L and 2.5L V6 2-stroke outboards.
With Ti-6Al-4V titanium construction, PVD coating, and a broached 5/32-inch Allen-key drive, it is an excellent upgrade for builders maintaining 135 HP, 150 HP, 175 HP, and 200 HP Mercury engines, XR2, XR4, XR6, XRi, 200 Pro Max, and 225 Pro Max applications.