ARP Head Studs & Engine Fasteners

ARP Head Studs & Engine Fasteners

ARP head studs replace factory head bolts with precision-machined threaded studs that provide more consistent and repeatable clamping force on the cylinder head gasket. Unlike head bolts that apply torque through both rotational and tensile forces, head studs allow the nut to be torqued concentrically on a stud that is already stationary, producing more even clamping load across the entire head gasket surface.

Popular ARP Head Stud Applications

ARP head studs are available for a wide range of performance and turbocharged engines including the Subaru EJ series, Honda K series and B series, Mitsubishi 4G63 and 4B11, Honda Civic and Integra, Toyota 2JZ-GTE, Nissan SR20DET and RB series, GM LS series, Ford Coyote and 5.0, and Dodge/Chrysler HEMI applications. ARP offers both 8740 chromoly and ARP2000 alloy head stud kits, with the ARP2000 material providing approximately 20 percent higher tensile strength for high-boost applications above 30 psi.

Why are head studs preferred over head bolts on boosted engines?

Head studs are preferred on turbocharged and supercharged engines because higher combustion pressures place greater stress on the head-to-block joint, requiring higher clamping force to prevent head gasket lift and combustion gas leakage. ARP head studs allow precise torque value targeting during installation using the included ARP Ultra-Torque lubricant, which eliminates friction variation between torque applications and ensures every stud is loaded to the same clamping force. This consistency is particularly important on engines that require multiple heat cycles and retorquing during initial break-in.

Do head studs require machining or special installation procedures?

ARP head stud installation requires installing the studs hand-tight or with a stud driver into clean, dry threaded holes in the block. The use of ARP Ultra-Torque lubricant on the threads and under the nuts is required for accurate torque readings. Some applications with interference-fit stud holes require applying thread sealer to the lower stud thread if the holes are open to the water jacket. ARP includes application-specific torque specifications and installation instructions with every head stud kit.

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