The Lucas 440300501 pinion drive is a genuine replacement component designed for Lucas M50, M50G, M50L, M50R, M50S, M50T, M50X, M50Y, M50Z series starter motors. This essential starter motor part features a 30.5 mm outer diameter, an overall length of 51 mm, and 10 splines for reliable engagement. It operates with a clockwise rotation and utilizes a robust roller clutch drive type, ensuring efficient and consistent starter performance in various applications.