Edelbrock Rollin Thunder Camshaft Hydraulic Roller for Mark IV Big-Block Chevy 500+ CIEdelbrock Rollin' Thunder Camshaft #2263 is designed for 500+ Mark IV and Gen V engines from 1967 95 and produce optimum torque from the low end to the mid range. Rollin' Thunder camshafts match with Performer manifolds for vehicles operating from off idle to 5500 rpm. They are smooth idling cams for daily drivers, trucks, vans, RVs and 4x4s. You can expect a major improvement in throttle response and torque. In the manifold section you'll find torque