5-Speed Gearbox Conversion Kit for 3-Bearing Engine

The Vitesse MGB gearbox conversion kit for 3-bearing engine models provides a modern 5-speed shifting experience for your classic MGB. Built around a brand new Mazda MX-5 transmission, this system features a custom Vitesse gearbox case, bellhousing, and machined billet front plate to ensure precise fitment in the original location. The kit significantly reduces weight by up to 13.5kg compared to the factory unit, while the 5-speed gear ratios are optimized to work perfectly with the standard 3.909:1 differential. The system comes fully assembled and includes a bespoke shift lever, concentric slave cylinder assembly, prop shaft, spigot bush with needle roller bearing, and a complete geomet-coated fixing kit. A mechanical speedometer sender and cable are included as standard, though an optional Smiths electronic speedometer kit is available for those seeking higher accuracy or an end to needle bounce. For electronic speedometer users, note that 4" instruments are for chrome bumper models and 3" versions are for rubber bumper models; both are available only in negative earth configurations. Professional installation is recommended if the fitment does not progress easily, particularly given the age of the vehicle. This kit is compatible with all 1962-80 MGB variants featuring a 3-bearing engine, though it is not intended for use with other engine configurations.