Chevrolet Big Block Adv. Duration: 296/302Duration @ .050": 243/249Lift: .640/.640Lobe Separation: 112 LCIncluded Lifters: 91161 Hyd. Roller3000-6500. Lopey idle, broad mid-range power. 10.0:1 CR, 3000+ stall.
Chevrolet BB Mark IV 396-502 1965-1996Advertised Duration: 282/288Duration @ .050": 229/235Valve Lift w/1.70 Rockers: .589/.601Lobe Separation Angle: 110Intake Centerline: 1062000-5800 Fair idle, Performance usage. Mid-range torque & horsepower.