Hydraulic Roller - Thumpr: High performance street, stock converter ok, best with 2000+ converter and gears. Choppy/thumping idle.; 283/303 Advertised Duration, 227/241 Duration .050", .513"/.498" Lift, 107 Lobe Separation; 1900 to 5600 RPM range; Must use bronze tip fuel pump pushrod when using high pressure or high volume pump;
