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Eagle forged 4340 steel crankshafts are our top-of-the line competition crankshaft. Forged from ASME-certified 4340 steel in a non-twist forging, these cranks undergo X-Ray inspection, magnafluxing, and sonic testing to ensure quality. Journals are ground to exact specs and polished with our unique QPAC micropolishing system to achieve a roughness average of less than 2 RA. Target bobweight is held to within 2% of specification to help eliminate guesswork when balancing. All Eagle forged 4340 steel cranks are designed for internal balance without the need for heavy metal unless your bobweight is higher than the design target bobweight of the crank. Each crank is nitrided for superior hardness and wear protection. .125" fillet radiuses are used on each journal for increased rigidity and strength. For this reason, chamfered or narrowed bearings must be used. Eagle forged 4340 cranks are intended for the most severe competition engines including nitrous, forced induction, and exotic fuels. For added stability at high rpm and high loads, choose a crank with center counterweights - available for select applications.