ARP L19 Head and Main Studs are recommended for VG30DE(TT) engines trying to achieve maximum horsepower and RPM range. Through our research and testing we have found that at very high power levels OEM Head Bolts or typical ARP Head Studs can stretch causing the cylinder heads to lift off of the block blowing head gaskets in addition to crankshaft walk leading to crankshaft failure. The solution to this is to increase the clamping force (torque) on the cylinder head and main cap fasteners. In order to do this the strength and resistance to stretch must be increased on the fasteners. For that purpose we now offer ARP L19 Head and Main Studs.
L19: This is a premium steel that is processed to deliver superior strength and fatigue properties. L19 is a very high strength material compared to 8740 and ARP2000 and is capable of delivering clamp loads in the 230,000-260,000 psi range. It is primarily used in short track and drag racing applications where inertia loads exceed the clamping capability of ARP2000. Like most high strength, quench and temper steels – L19 requires special care during manufacturing to avoid hydrogen embrittlement. This material is easily contaminated and subject to stress corrosion. It must be kept well-oiled and not exposed to moisture.
Spend a few extra dollars on your engine for peace of mind knowing that it is secured with the best upgraded studs on the market.
L19 Head Stud Torque Spec : 110 ft-lbs w/moly lube on & under nut.
L19 Main Stud Torque Spec : 95 ft-lbs w/moly lube on & under nut.
Z1 recommends using the supplied ARP Moly Lube when torquing ARP fasteners.
Z1 Motorsports: ARP L19 Head & Main Studs - 
