A recommended upgrade for all TH350 applications behind engines producing between 400 and 800 foot pounds of torque. Manufactured from proprietary steel billet material, the shafts redesigned profile includes a torsional center, vastly improving power transmission. Undercuts behind the splines are eliminated, resulting in increased spline length and diameter, increasing spline engagement at the clutch housing interface over 20%. Improved press fit over OEM design reduces spline interface failures. Fully CNC machined, splined, and ground .