Finest Grade Billet: When designing components for the Porsche engine, material quality has to be top priority. Porsche engines built for High-Output applications have demanding requirements, for this reason every Shaftech crankshaft is made from 4340 high alloy steel. We go the extra mile to invest in billet stock made from bottom poured ingots produced to fine grain melt standards. These standards result in ultra pure material having an ASTM grain size of 5 to 7. Each Shaftech crankshaft is through hardened to our proprietary specification resulting in a final product that combines both stiffness and toughness. Less flex, improved bearing load distribution and greater fatigue strength all directly result from our billet material and heat treatments.