P-Series main bearings are the oldest members of the Clevite 77 bearing family and are intended for high-revving engines. To compensate for the high-load factors and distortion in these engines, these bearings have higher eccentricity and a high crush factor. P-Series bearings are built on steel backings with extra-thin overlays to prevent overlay fatigue. In addition, the oil grooves on most applications extend all the way around both halves for better oiling.