ZRP billet Crankshafts are constructed from 4340 steel. Every single ZRP Crankshaft is designed carefully from our experience for the best possible engine performance. Our crankshaft production process consists of very detailed inspections to ensure that they have the best quality and tolerance for extreme applications. The production process comprises from the following: CNC machining for more precise results, multi-stage heat treatment, Nitride process for hardening and heat treatment for superior wear resistance , Magna-fluxing for flawless surface finish, Shot peening for more improved fatigue resistance, Micro-polishing for longer bearing life and finally Journal radio disperse load stress. Our crankshafts also feature straight oil holes for best oiling to the rod journals. The Ultra light weight has drilled main and rod journals form weight reduction. The light weight which features knife edged shaped counterweights to reduce weight and increase crankshaft aerodynamics. Finally the standard design which feature solid counterweights for maximum durability and increased crankshaft momentum. ZRP uses Sunnen machine for unique crankshaft balancing. Our Crankshafts are balanced 1gr.cm +/- 0.1 for the 4 cylinders and 2gr.cm +/- 0.1 for the 6 cylinders. All ZRP Crankshafts are fully balanced and ready to install.