This is for the serious racer who requires the ultimate in drive and reliability, a spool reacts in the same way, every turn, every time. Since the spool is made from a single piece, there are no small parts to break or clutch plates to wear out and provide the most reliable solution for your power transmission needs. Our steel spools are made from 4140 chromoly steel billets, heat treated, finished machined and then blackened. These spools have been race proven in production car racing throughout Australia and New Zealand. Vehicle Applications: Vehicles fitted with Borg Warner M78 series housing and 31 spline axles.