W/P & Thermostat Housing Bolt Kit - 12pt. LS1/LS2

The ARP Water Pump & Thermostat Housing Bolt Kit for LS1/LS2 engines delivers OEM-quality fastening with performance-grade materials engineered for high-reliability engine builds. This 12-point bolt kit pairs chromoly construction with black oxide finish to resist corrosion while maintaining the structural integrity critical to coolant system pressure integrity. Designed specifically for GM's LS-series platform, this kit addresses the fastening requirements where factory bolts may compromise long-term durability under sustained boost, elevated coolant temperatures, or frequent thermal cycling.

ARP's chromoly bolt material offers significantly higher tensile strength than stock fasteners, reducing the risk of thread stripping or bolt failure in the critical water pump and thermostat housing locations. The 12-point head geometry provides engagement points for both standard and offset wrenches, improving accessibility in tight engine bay configurations common to LS1 and LS2 installations. Washers are included to distribute clamping force evenly and protect mounting surfaces from galling. Black oxide coating provides enhanced corrosion resistance in environments where coolant contact and moisture exposure pose degradation risks.

This fastening kit is essential for serious LS engine builders, performance shops, and users maintaining modified LS1/LS2 powerplants that demand superior hardware reliability. Whether assembling a street engine, track-duty power plant, or marine application where thermal stress and vibration are elevated, upgrading from OEM fasteners to ARP-grade bolts reduces the likelihood of coolant system leaks and catastrophic thermal failures. The kit's modest weight and compact dimensions make it easy to stock and deploy across multiple engine builds.