SLP's 1.85 RATIO ALUMINUM ROCKER ARM PACKAGE is designed as a true bolt-on replacement for LS3 engines. These rockers require NO valve cover or cylinder head modifications. OEM-quality aluminum construction and a roller bearing trunnion results in a 10% increase in valve lift over the stock 1.7 ratio rocker arms and gains of up to 12 horsepower over stock. Retainers, keepers and SLP high-lift valve springs are included to prevent coil bind. Includes all necessary installation hardware and detailed instructions. Rocker Arms Feature: Made from USA 2024 Aluminum Aircraft Extrusion Bearings are Torrington Full Compliment Needle Rollers Includes Rocker Arms (1.85 ratio) Includes new Rocker Arm Bolts Includes new Pedestals Includes new Retainers and Keepers No Modification to Valve Covers Needed All Instructions are included to complete the installation.