Eagle billet 4340 steel crankshafts are our top-of-the line competition crankshaft. We start with ASME-certified 4340 steel and machine every detail into the crankshaft. These cranks undergo X-Ray inspection, magnafluxing, and sonic testing to ensure quality just like all Eagle 4340 steel crankshafts. 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 billet 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 billet 4340 cranks are intended for the most severe competition engines including nitrous, forced induction, and exotic fuels. Eagle billet 4340 steel cranks also include our ESP Armor surface finishing process to ensure a perfect finish.