No they are P series.
Clevite 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 constructed of tri-metal cast copper lead. They have a steel back for support, a cast copper lead lining to withstand the loads of engine operation, and an electroplated babbit overlay on the running surface to provide searing surface qualities. In addition, the oil grooves on most applications extend all the way around both halves for better oiling.
Clevite P-Series main bearings are an ideal design, producing a degree of conformability, embedability, slipperiness, and fatigue resistance, not found in original equipment and competitive bimetal bearings.
