Cam and lifter kit for Big Block Chevy engines; CL-Kit includes cam, lifters, assembly lube, instructions and decals; Hydraulic - Xtreme Energy: High performance street, very strong mid-range, with headers and 2000+ stall.; 274/286 Advertised Duration, 230/236 Duration .050", .552"/.555" Lift, 110 Lobe Separation; Valve spring upgrade required