Rocker Arm shafts, Rocker Arm Stud Kit, Head Bolt Kit and Performance Roller Rocker Arms are included in this kit. Rocker Arm Shafts. Replace broken or worn OEM pieces with stronger, more durable S&S performance parts. Direct replacement for stock parts. Hardened and surface ground for ultimate precision and durability. Rocker Arm Stud Kit. Extend the life of your cylinder heads. Prevent damage to Rocker Arm Towers. Install studs and safely re-torque nuts. Black Oxide Finish. 12 pt Nuts. Head Bolt Kit. Heat Treated 8640 Steel. 200,000 psi ultimate tensile strength. 14% increases in strength over stock. Stronger material than stock Head bolts. Durable Black Oxide Coating. 9/16" 12-point head with integral washer. Formed threads. Cold Formed Head. Reusable. Forged Roller Rocker Arms. Forged from 8620 steel for greater strength. Designed using Finite Element Analysis (FEA).