Competition Cams 850-16 Hydraulic Roller Lifters for Small Block Chevy 305 and 350c.i. Engines Originally Equipped with Hydraulic Roller Cam, 1987-Present, Including LT1 and LS Series .842 diameter; 122g weight; 2.66 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