Edelbrock Rollin Thunder Camshaft Hydraulic Roller for Chevy 348/409Edelbrock Rollin' Thunder Camshaft #2268 is designed for 348 409 (W Series) engines from 1958 65 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