American Motors L6 199-258/4.0L
Advertised Duration: 257/263
Duration @ .050": 203/209
Valve Lift w/1.60 Rockers: .443/.448
Lobe Separation Angle: 110
Intake Centerline: 106
Valve Lash: Hyd./Hyd.
1000-4400. Mild street performance, strong low end torque.

American Motors L6 199-258/4.0L
Advertised Duration: 269/269
Duration @ .050": 215/215
Valve Lift w/1.60 Rockers: .475/.475
Lobe Separation Angle: 112
Intake Centerline: 108
Valve Lash: Hyd./Hyd.
1400-5000. Moderate street with headers and better carb/intake, fuel injection.

American Motors L6 199-258/4.0L
Advertised Duration: 275/275
Duration @ .050": 221/221
Valve Lift w/1.60 Rockers: .501/.501
Lobe Separation Angle: 108
Intake Centerline: 104
Valve Lash: Hyd./Hyd.
1800-5600. Fair idle, hot street, aftermarket induction & headers a must, not for fuel injection.