Note: The hydraulic lifter in a car's engine uses oil pressure to adjust a plunger and take up all the clearance in the valve train. This helps to ensure less engine noise and longer reliability, due to less wear and tear. Hydraulic lifters can begin to fail through normal use of a vehicle. After several years of running the engine of your vehicle, the hydraulic lifters within the valves can become laden with sludge, and other contaminants in the valve, that they start to wear out. New hydraulic lifters can make a tremendous difference in the way that a vehicle runs as well as how the engine sounds. Be sure to have your engine lifters replace with aftermarket replacement engine lifters as soon as it starts to give you trouble. Fitment: for Chevrolet small block 265 1955-1957 4.3L for Chevrolet small block 283 1957-1967 4.6L for Chevrolet small block 327 1962-1969 5.4L for Chevrolet small block 350 1967-2003 5.7L for Chevrolet small block 302 1967-1969 4.9L for Chevrolet small block 307 1968-1973 5.0L for Chevrolet small block 400 1970-1981 6.6L. Lifter Outside Diameter: 0.8425 Lifter Style: Hydraulic Roller Link Bar: Vertical NOTE: This Retro fit Hydraulic Roller Lifters are not original parts, the mention of brand names and any related model designation above is only for purposes of demonstrating compatibility. Please double check the part number of your item,matching information is for reference only. If you are unsure of the item, please contact us before buying to avoid unnecessary return. The picture can tell more than we can, what you see is what you will receive,please make sure it will fit your machine before bidding it. Please check pictures for more details.