COMP Cams 1601-1 Ultra Pro Magnum Roller Rocker Arm with 1.52 Ratio and 3/8" Stud Diameter for Small Block Chevrolet For Small Block chevy applications, 1.52 ratio, 3/8 inch Studs Investment cast 8650 chromemoly body and arched, web-like design deliver increased strength and rigidity while reducing moment of inertia Unique black oxide exterior finish helps prevent corrosion, thus increasing durability Optimized retainer and valve spring clearances allow use of most diameter springs, retainers and +.050 inch locks without clearance or fitment issues Feature oversized trunions, precision sorted needle bearings and hardened roller tips