These Tri-Metal 77 engine bearings combine the strength of a copper-lead alloy layer with steel backing and an electroplated babbitt metal. The steel backing provides strength and durability; the babbitt overlay provides the critical surface characteristics of slipperiness and conformability. This ideal design has properties not even found in many original equipment bearings. Clevite offers main bearings, rod bearings and cam bearings in this series. H Series - Best to start with when unsure which bearing to choose. Medium level of eccentricity and high crush. Enlarged chamfers for greater crankshaft fillet clearance. Made without flash plating for better seating. Use with crankshafts that have oversized fillets. Use with engines that run mid-high RPM range. Contact patterns should ideally cover 2/3 to 3/4 of the bearing surface. P Series - Typically the greatest level of eccentricity. Rods and mains have high crush for maximum retention. Most are fully grooved to maximize oil flow to rod bearings. Reduced overlay thickness to prevent overlay fatigue. Use where extremely high RPMs cause severe rod bore close-in. Use where higher eccentricity is desired to narrow bearing contact patterns. V Series - This series essentially duplicates Clevite's former Vandervell parts. Typically low to medium eccentricity. Not available with oversized chamfers. No flash plating on the steel back. All Clevite main bearing sets use a single-piece thrust bearing. Narrowed parts available to accommodate increased crankshaft fillet clearance. Lead-indium overlay offers slightly better conformability. M Series - These are special purpose bearings having a nominal .005" thick Babbitt lining on a hardened steel back. They are intended mainly for Blown Fuel engines where severe crankshaft deflections cause edge loading of the bearings. Under these operating conditions bearing service life will be very short. Frequent inspection and replacement is recommended. Part Number Key H - High-Performance. HD - High-Performance bearing with dowel hole. HK - High-Performance bearing with moly/graphite coating. P - Standard Clevite 77 tri-metal bearing. M - Blown Fuel Engine bearing for severe crankshaft deflections & edge loading. N - High-Performance Narrowed for greater crankshaft fillet clearance. HG - High-Performance full angular grooved bearing. V - High-Performance with Lead Indium overlay (On Main Sets this indicates partial groove also). VG - High-Performance with Lead Indium full angular grooved bearing. D - Bearing has a dowel hole. K - Tri-Armor coated bearing. X - Bearing has .001 more oil clearance than standard. XX - Bearing has .002 more oil clearance than standard. A or AL - Indicates Aluminum bearing material. Note: Clevite main and cam bearings are priced as sets; rod bearings are priced each.