One often overlooked part when building an engine is the bearings. Getting a quality set of bearings can directly determine the longevity of your engine. These are Clevite's H-Series Bearing which is considered their Race Bearing. We use Clevite Race Bearings in many of the race engines we build here. These bearings are ".25", they are .25mm THICKER than stock. Use these when your crank is cut .010". Clevite H-Series bearings were primarily developed for NASCAR racing, but are well suited to other types of competition engines. They're especially good for engines that run at medium-to-high revs. They have hardened-steel backings with thin overlays and a high crush factor, plus a medium level of eccentricity. H-Series bearings have enlarged chamfers at the sides for greater crank-fillet clearance and are made without flash plating for better seating.