Designed using Finite Element Analysis (FEA) and forged from 8620 steel for strength. Eliminate thrusting on valves for decreased wear on the valve train. Rocker geometry is better suited to high-lift camshafts. Bushings are 50% longer than stock, increasing the time between rebuilds. Oil is sprayed directly on the valve springs, reducing the potential for valves breaking due to overheating. Compatible with stock or S&S CNC-machined heads. 1.640 ratio. Capable of 0.650" max valve lift. Serviceable and rebuildable. Sold in a set of four. Made in the U.S.A.