NITTO 4340 Billet Steel crankshafts are manufactured from high quality true billet round bar stock. Most other aftermarket crankshafts are manufactured using cast forged material, which is a much cheaper manufacturing process and hence carry a cheaper price tag but their performance, strength and horsepower capabilities are significantly compromised compared to that of a true billet crankshaft. An engine with a 4340 billet steel crankshaft will rev faster and cleaner due to the different harmonics produced from the high grade material.