Select which type or series preferred, then select size.

A stock replacement trimetal bearing for most older engines with about a 0.001-inch babbit (lead-tin-copper) overlay electroplated onto the bronze. A "P" might be all that's offered for old-school engines made prior to the early 1960s.

H-series:

The H-series Clevite-77 high-performance bearing 90 percent of Clevite's performance bearing sales. It uses the same babbit formula as a P, but at about half the thickness to hold up better under heavy loads typically encountered in high-performance engines. "HN" variants are slightly narrower to clear enlarged fillets typical of most high performance aftermarket cranks.