Good for 4.25'' stroke with 114''-117'' engine looking for an agressive bolt in Produces a wide powerband Responds very well to increased bore and/or compression, exhaust system and air cleanerUse of performance valve springs is not required but may result in a quieter, smoother running valvetrain.Cam specs measured in the engine on the lifter @ 0.050 using a 1.61 rocker arm ratio.Feuling does not recommend tuning beyond stock emissions standards.