P-Series rod bearings are the oldest members of the Clevite 77 performance-bearing family. They're intended for high-revving engines, especially those where the high rpm cause the rod bores to narrow. To compensate for this distortion, they have higher eccentricity and a high crush factor. P-Series bearings are built on hardened-steel backings with extra-thin overlays, and their oil grooves extend all the way around both halves for better oiling. Lower sections have dowel holes for use with aluminum rods, and there are extra-clearance variations available with an additional 0.001 in. of clearance.