Proform Poly Lock Rocker Arm Adjusting 66935 | MyTires4Less

The Proform Poly Lock Rocker Arm Adjusting Nuts are designed to securely hold valvetrain adjustments, preventing them from backing off under engine vibration and heat. These specialized nuts feature a locking mechanism, often a set screw, that provides a positive lock on the rocker arm stud. They are a common upgrade for performance engines using adjustable valvetrains, ensuring consistent valve lash. Proform offers various valvetrain accessories to complement their rocker arms and other components.