Competition Cams 8931-16 Retro-Fit Hydraulic Roller Lifters for Ford 289-302 Small Block and 351 Windsor Non-Roller Engines .875 diameter; 146g weight; 2.60 seat height Performance replacement for stock hydraulic roller lifters or retro-fit hydraulic roller lifters for non-roller blocks Decrease friction and increase longevity when directly compared to flat tappet lifters Accept much more aggressive cam profiles than flat tappet lifters will allow