Hydraulic Roller - Xtreme Fuel Injection (XFI): Excellent torque for throttle body 305 or 350. Good economy with added power.; 252/264 Advertised Duration, 202/212 Duration .050", .550"/.546" Lift, 113 Lobe Separation; 1000 to 5000 RPM range; Recommended use with 1.6 rocker arm ratio; Must use bronze tip fuel pump pushrod when using high pressure or high volume pump
