As the premium line of crankshafts offered by Lunati, Signature Series Crankshafts are the strongest you will find for your engine. The specialized non-twist 4340 forged steel construction comes completely profiled and detailed to our racing specs. Many design features such as gun drilled mains, lightened rod journals, micropolished journals and a windage reducing contoured wing counterweight profile make the Signature Series the best choice for serious racers.