At KING Engine Bearings they learn from racing experiences and apply what they learn to help make better bearings for race engines. Racers like Eddie Hill and Jay Payne have benefited from KING innovations like: Alecular? Bearing Material -- KING developed this alternative to the traditional tri-metal bearings construction. KING bearings have a single deep (. 012" - . 015") layer of Alecular material, an exclusive alloy of aluminum, tin, copper and other metals, on the steel backing. This gives superior embedability. "Bull's Eye" Bearing Wall Tolerance -- With advanced quality control procedures, KING is able to maintain rod and main bearing wall thickness tolerances at an amazingly tight plus or minus . 0001" -- far tighter than other manufacturers. "MaxFlange®" -- a manufacturing principle that lets racers and street engine rebuilders save engines with borderline crankshaft end play situations without additional machining. Precisely-controlled bearing flange length is the secret. King originated this manufacturing technology.Pit Stop USA offers King Alecular Pro Series Main Bearings - SB Chevy 350 (1976-98), SB Chevy 400 (1970-80) w/ Grooved Uppers - .020" MB 557HP 020 at low everyday prices. Be sure to check out all of our products from King Engine Bearings including King Engine Bearings King Alecular Main Bearings - SBC.