When Manton decided to make these rocker shafts valve train stability was there main concern so they manufactured there shafts to be very strong and provide the racer with a superior part. Choice of material is .250” wall thickness 4130 Chromoly steel. Each pre-heat treated shaft is prepared in a four axis milling center, then center less ground undersize, hard chromed oversize and finish ground to size. This leaves a hard chrome surface .008” deep, providing excellent wear protection in any application, including use in your daily driven street Hemi.
Manton Fat Head shafts feature a new type of radial oil transfer passage which provides full time oiling to the pushrod and adjusting screw. Without this new oiling feature the stock oiling passage is shut off as soon as the rockerarm starts to open the valve. All of Manton shafts use a threaded plug to seal each end. This eliminates any chance of an oil leak from worn or poor fitting O-rings.