Thermostat Housing Bolt Kit - 12pt. LS1/LS2

The Thermostat Housing Bolt Kit - 12pt. LS1/LS2 is an essential fastener upgrade for LS engine builders and performance enthusiasts tackling high-heat applications. OEM thermostat housing bolts often lack the clamping force and reliability demanded by modified engines, custom cooling systems, or aggressive track builds. This bolt kit replaces those weak factory fasteners with premium-grade hardware engineered to maintain consistent seal integrity under extreme temperature cycling and elevated coolant pressure.

Featuring 12-point head geometry, these bolts distribute load more evenly across the housing and intake manifold mating surface compared to 6-point designs, reducing the risk of bolt stretch and housing distortion. The 12-point configuration also provides superior tool engagement and precise torque control during installation—critical when working near intake ports and cooling passages where over-tightening can crack aluminum castings. Engineered to ARP specifications (MPN 134-7401), these fasteners exhibit exceptional tensile strength and corrosion resistance, ensuring they won't seize or corrode even in high-humidity storage or marine environments.

LS1 and LS2 engine swaps, turbo conversions, and supercharger installations all benefit from this upgrade, as modified cooling systems often run higher pressures and tighter tolerances than stock configurations. Whether you're rebuilding a 6.0L truck engine, preparing an LS7 for competition, or ensuring long-term reliability in a street-strip hybrid, this bolt kit delivers the clamping force and durability required for peace of mind. Installation is straightforward—simply torque to specification using a calibrated wrench and a 12-point socket for even fastener engagement.