ARP Main Stud 4-Bolt Kit Main 12PT Nut For Nissan VR38DETT 3.8L DOHC ARP main stud kits are made from 8740 chromoly steel and have a 190,000 psi tensile-strength rating. They are precision centerless-ground and thread-rolled to Mil-S-8879 specs, with a black oxide finish for corrosion resistance. The kits come complete with hardened washers and high-strength hex nuts. Upgrade your engine's strength and durability with ARP Main Stud 4-Bolt Kit Main 12PT Nut. Made from top-quality chromoly steel, these studs have a high tensile-strength rating and undergo rigorous precision grinding and threading processes. With a corrosion-resistant black oxide finish, these kits come equipped with hardened washers and high-strength hex nuts for optimal performance. Trust ARP to provide the essential components your engine needs to perform at its best.