12mm x 1.25/1.75 Stud Long Broached

The ARP 12mm x 1.25/1.75 Stud Long Broached (AU3.965-1LB) is a precision chromoly fastener engineered for high-performance engine assembly and critical fastening applications. This 3.965-inch long broached stud combines ARP's strict manufacturing tolerances with black oxide corrosion resistance, making it suitable for demanding automotive and motorsport environments where reliability under load is non-negotiable.

The dual thread pitch design—accommodating both 12mm x 1.25 and 12mm x 1.75 threads—provides flexibility for applications requiring either metric fine or metric standard pitch fastening. Chromoly material offers superior tensile strength compared to standard steel studs, enabling consistent clamping force and resistance to relaxation during thermal cycling. The broached design ensures precise engagement without galling, critical when working with aluminum or composite materials where surface damage during installation can compromise seal integrity and structural performance.

ARP studs are specified by engine builders, machine shops, and performance fabricators for cylinder head fastening, intake manifold mounting, and other load-critical assemblies where standard hardware fails to meet torque specifications or repeated cycling demands. The black oxide finish provides baseline corrosion resistance in engine bay environments, though builders working in salt air or high-moisture conditions often apply additional protective coatings. This is a single stud; quantities required depend on your specific application and fastening pattern.