Main Stud KitSmall Block Chevy 3504-Bolt Style190,000 psiIncludes 12-Point Nuts, Washers Speedmaster engine studs are premium-grade, race-quality studs that are created from aircraft quality 8740 high tensile strength chromoly steel, withstanding up to 190,000 PSI .They are ground and thread-rolled after heat treatment to ensure the exacting tolerances that Speedmaster requires for all of their fasteners. This ensures strength and consistent torque readings. All kits come complete with 4130 heat-treated, parallel-ground washers and high-strength 12-point nuts.