Eagle forged 4140 steel cranks bridge the gap between the entry-level cast cranks and the all-out competition 4340 steel cranks.  The design is identical to our 4340 steel cranks, but they are forged from 4140 steel. 4140 steel has about 80% the strength that 4340 has, but at a much less expensive price. It is still a chromium - molybdenum steel, it just lacks the nickel content of 4340 steel. Eagle forged 4140 steel cranks are an excellent choice for most competition engines including limited nitrous or forced induction. We recommend our 4140 steel cranks for use in engies up to about 1200hp.