Mopar Main Stud Kit - 5.9L Cummins 2-Bolt

The Mopar Main Stud Kit - 5.9L Cummins 2-Bolt by ARP is the foundation upgrade every serious Cummins diesel builder needs when planning high-output engine modifications. Factory main cap bolts are a critical weak point in stock 5.9L diesel architecture, prone to yielding and failure under elevated boost, increased fueling, or aggressive towing loads. This stud kit replaces those vulnerable fasteners with ARP's premium all-Alloy steel construction, delivering the clamping force and fatigue resistance required for reliable engine internals during sustained power increases.

ARP main studs are manufactured from proprietary Alloy steel and shot-peened for superior fatigue strength and crack resistance compared to OEM bolts. The 2-bolt configuration references the two fasteners per main cap required on first-generation 5.9L Cummins platforms, and each stud is precision-machined with ARP's characteristic micro-polished finish to eliminate stress concentrations. Pre-stretch technology ensures consistent clamping load across all fastening points, preventing load loss from vibration and thermal cycling that commonly undermines factory hardware during heavy turbo diesel operation.

This kit is essential for 5.9L Cummins engines running compound turbo setups, aggressive tuning, or continuous high-RPM use—particularly in dedicated pulling trucks or daily-driven builds seeing 450+ horsepower. Proper installation requires torque to yield methodology and ARP's recommended torque specifications to achieve correct preload; undersizing fastener loads risks catastrophic engine failure, while excessive torque strips studs. The lightweight 4.3 lb kit packages complete stud coverage in a compact format suitable for bench assembly or in-frame installation, making it ideal for both engine-out rebuilds and careful in-vehicle replacement.