This is the Speed Pro verison of the Duntov Camshaft for the 283 Chevy (3736097)Mechanical Flat TappetDuration @.050 in. 228/230Valve LIft .395 int. .401 exh.SBC 283 Sealed Power camshafts are designed and manufactured for maximum engine durability. Our camshafts are precision-ground and hardened to ensure OE performance and meet emission specifications.Sealed Power camshafts mate easily with new lifters or followers, and maintain correct timing to help eliminate indexing errors. Sealed Power camshafts are available for a wide variety of vehicle applications. They ensure component compatibility and proper valvetrain geometry.Sealed Power is a proven leader in camshaft technology and manufacturing.