Bellhousing Bolt Kit - 12pt. GM V6/V8

The ARP Bellhousing Bolt Kit for GM V6/V8 engines is a precision fastener set engineered for high-performance engine builds where OEM hardware cannot meet sustained load demands. This 12-point head bolt kit supplies six 3/8-16 chromoly fasteners rated for the critical bellhousing-to-block interface—a junction that experiences substantial shear and tensile forces during acceleration, engine braking, and transmission engagement. ARP's chromoly construction and black oxide finish provide both strength and corrosion resistance in engine bay environments where ferrous fasteners face thermal cycling and moisture exposure.

Each bolt measures 1.375 inches in length and features a 12-point head geometry that allows precise torque application without the rounding damage common to 6-point fasteners under high-load conditions. The kit includes matching washers, critical for distributing clamp load across the bellhousing surface and preventing fastener pull-through into aluminum or cast-iron mounting bosses. Chromoly bolts yield at higher stress levels than standard steel, maintaining clamping force during engine detonation events or transmission shock loads. The black oxide surface provides reliable corrosion resistance while maintaining the precise surface finish needed for consistent torque-to-clamp relationships during installation.

This fastener kit is intended for engine builders, performance technicians, and serious enthusiasts assembling or rebuilding small-block and big-block GM V6 and V8 engines for street performance, track duty, or high-horsepower applications. The bellhousing interface is non-redundant—failure of standard fasteners can result in bellhousing separation and catastrophic drivetrain damage. ARP hardware eliminates this failure mode by providing fasteners with yield strength well above OEM specification, making this kit essential for any engine where power output exceeds factory baseline or where repeated high-load cycles demand absolute reliability.