Reduced Travel OE-Style Hydraulic Roller Lifters. When dealing with full travel lifters certain engines respond better to a light pre-load because it recovers more quickly from any bad harmonics in the valve train. Others work better with a heavy pre-load because oil volume is reduced under the plunger which increases stiffness. COMP Cams Reduced Travel Hydraulic Roller Lifters allow you to have the advantages of both light pre-load and reduced oil volume producing the most stable and highest revving hydraulic lifter available. Applications: Ford Small Block: Use in Ford OE 302/351W blocks equipped with hydraulic Roller lifters/Roller lifter provisions. Use COMP Cams specially designed Ford Hydraulic Roller Retro-Fit Kit for 289-302 351W 351C 351M 400M. Use in Aftermarket Blocks with Roller lifter provisions or use Ford Hydraulic Roller Retro-Fit Kit. Specifications: Includes (16) .875" Diameter 128g Weight 2.60" Seat Height.