ARP Stainless Rear End Cover Bolt Kit for GM 12‑Bolt — 170,000 PSI, Precision Threads

ARP 4373002 is a stainless-steel bolt kit designed to replace and upgrade the rear end cover fasteners on GM 12-bolt differentials, delivering superior strength and corrosion resistance while including matching washers.

These bolts are manufactured by ARP under controlled in-house processes to meet high quality standards. Machined threads and a 170,000 psi tensile rating give the hardware much greater load capacity than typical OEM or Grade 8 bolts, and the stainless finish resists rust while adding a polished look to painted or chrome differential covers.

How will these bolts improve my GM 12-bolt rear end?

Swapping stock fasteners for the ARP stainless set increases clamping reliability and reduces the chance of thread failure under stress. The precise machining ensures even engagement, which helps maintain proper cover sealing and alignment over time.

• 170,000 psi tensile strength for enhanced durability
• Precision-cut threads for secure fit and consistent torque
• Stainless material prevents rust and staining in exposed areas
• Includes washers for correct load distribution and installation

Will the stainless finish affect the look of my differential?

The bright stainless surface creates a clean contrast against painted OEM covers and complements chrome aftermarket covers for a more finished appearance. Because the material resists discoloration, the visual upgrade is long-lasting with minimal maintenance.

• Lustrous stainless contrasts with dark or painted covers
• Works well with chrome-plated aftermarket covers
• Low upkeep—resists rust and staining
• Uniform appearance thanks to quality machining

Are these bolts strong enough for heavy-duty or performance use?

Yes — with a 170,000 psi rating these fasteners exceed the strength of standard hardware and even surpass Grade 8 in tensile capacity. That higher strength reduces the risk of stretch or breakage under high torque or load conditions commonly encountered in performance and towing applications.

• Tensile rating significantly higher than Grade 8 equivalents
• Designed to withstand higher clamping and shear loads
• Precision threads lower the chance of stripping during service
• Washers included to maintain even clamping pressure

What should I know about fitment and installation?

The kit is intended specifically for GM 12-bolt rear end covers and includes the correct quantity and type of bolts and washers for a proper replacement. Standard hand tools are sufficient for installation, but following OEM torque specifications and using proper thread engagement practice is recommended.

• Made for GM 12-bolt differential covers—confirm vehicle application before purchase
• Comes complete with matching washers for correct load distribution
• Install with recommended torque values and even cross-pattern tightening
• Use clean threads and check for proper engagement to avoid leaks

Who is this for: The ARP 4373002 kit is aimed at enthusiasts, restoration builders, and technicians who want a durable, corrosion-resistant fastener upgrade for GM 12-bolt rear ends. It suits anyone replacing worn or corroded hardware, upgrading to a higher-strength solution for performance or towing, or adding a polished visual detail to a visible differential cover.