Crane Cams' Energizer (Formerly Hi-Intensity) Roller Rocker Arms - Needle bearing fulcrum and roller tip reduces friction, lowers engine oil temperature, improves response, increases HP and RPM. Aerospace vacuum die-formed aluminum main body offers extreme strength and light weight. Great for street and moderate race use. Die-formed aluminum body is larger than stock, may require modifications to stock valve covers for clearance. Cannot be used with late Chevy 90° V-6 and small-block V-8 "Center Bolt" valve covers. Will not fit 90° V-6 or small-block V-8 self-aligning 88-99 heads.Pit Stop USA offers Crane Cams Energizer Aluminum Roller Rocker Arm Set - SB Chevy Standard - 1.6 Ratio, 3/8" Rocker Arm Stud 11746-16 at low everyday prices. Be sure to check out all of our products from Crane Cams including Crane Cams Aluminum Roller Rocker Arms - Small Block Chevy.