Use the Clevite MS-2218H-.026mm H-Series Main Bearing Set .026mm Undersize when building your 2001-2013 GM 6.6L Duramax. Clevite H-Series Bearings were developed primarily for NASCAR type racing, but are suitable for all types of competition engines. H-Series bearings have a medium level of eccentricity and high crush. These bearings also have enlarged chamfers for greater crankshaft fillet clearance and are made without flash plating for better seating.Â Use H series bearings with crankshafts that have oversize fillets and where engines run in the medium to high RPM range. If you arent sure which type of performance bearing to start with, the H series bearing will be your best choice. Features:Â .026mm Undersize Clevite H-SeriesÂ Main Bearing Set Note:Â Undersize bearing can be used but the crankshaft must be rehardened with nitride heat treatment. Requires thrust washer set TW-610S (see below).