Clevite Main BearingsThese bearings were developed primarily for use in NASCAR type racing, but are suitable for all types of competition engines. H-Series bearings have a medium level of eccentricity, high crush, and rod bearings have a hardened steel back and thin overlay. These bearings also have enlarged chamfers for greater crankshaft fillet clearance and are made without flash plating for better seating. Bearings with .001” extra clearance are available for standard size shafts and carry the suffix HX” (X = extra clearance). Use H-Series bearings with crankshafts that have oversize fillets and where engines run in the medium to high RPM range. If you aren’t sure which type of performance bearing to start with, the H-Series bearing will be your best choice.