Clevite 77 manufactures a full line of exclusive TriMetal? copper lead high performance bearings. Choose the bearing series which best suits the intended application. "P" Series - Traditional Clevite 77 TriMetal? bearings have high crush qualities for maximum bearing retention, high eccentricity to account for bore distortion and reduced overlay thickness to prevent fatigue. "H/HN" Series - Race engine builders prefer their lack of fl ash plating, medium levels of eccentricity, enlarged chamfers for additional crankshaft fillet clearance and high crush. When a "D" is added to the part number suffi x, bearings include dowel pin holes; an "X" suffix indicates bearings with . 001" added oil clearance, while a "K" suffix indicates bearings which are coated with moly/graphite, an anti-wear agent that also offers protection through a broad temperature range. NOTE: "HN" series are only available as rod bearings and are engineered to provide increased crankshaft fillet clearance. Clevite 77(R) engine bearings have an extensive, long-standing history with racing. Our Clevite 77 product has been winning NASCAR(R)-sanctioned races since 1948, and is the exclusive bearing of NASCAR Performance. Since development of the first precision insert-type bearing in 1929, Clevite 77 engine bearings have set the pace for engineering quality. Clevite 77 engine bearings are built above industry standards for strength and durability even exceeding the highest standards set by Heavy Duty engine manufacturers. The majority of Clevite 77 engine bearings utilize a superior TriMetal? design first developed by Clevite 50 years ago and perfected over time. This design incorporates the strength of a copper-lead alloy layer on a precision steel back and finally, a precision electroplated white metal "babbitt" surface layer. TriMetal is an ideal design, producing a degree of conformability, embedability, slipperiness and fatigue resistance, not found in many original equipment and competitive bi-metal bearings. All Clevite 77 Engine Bearings are color coded for quick and positive identification of undersizes. The possibility of confusion or errors in installation is virtually eliminated by checking the color code on the side of each bearing. Clevite 77 also offers the most extensive line of performance engine bearings in the market. Their range of performance engine bearings is designed to provide winning results even in the most demanding applications. Their involvement in INDY, NASCAR, ARCA, NHRA and IHRA racing as well as other forms of motorsports have proven Clevite to be the leaders in engine bearing technology both on the track and off. It's no wonder that Clevite 77 is used more often than any other bearings in cars worldwide and in most race cars. In addition, Clevite 77 has been in most winning engines at Indianapolis and NASCAR. and that's why, year after year, quality engines everywhere turn on Clevite 77 bearings.Pit Stop USA offers Clevite H-Series Main Bearings - Full Groove - Standard Size - Tri Metal - Ford - 351M, 351W, 400 - Set of 5 MS981H at low everyday prices. Be sure to check out all of our products from Clevite 77 including Clevite 77 Main Bearings - Small Block Chevy.