For sale, new, unused, complete gearbox kit to convert your classic 4-speed gearbox to 5 speed. 300€, or whatever that converts to in your local currency on day of payment, + shipping.
_5 gear cogs
_5 row primary drive (spring gear/ layshaft)
_selector box with 6 positions: 5 for gears, 1 for neutral (the ratchet plate/selection platter can be reinstalled in different box to keep use of neutral switch on US PEs and LMLs, for instance.
_rebuild kit for spring gear
This kit uses your original secondary drive (wheel axle) and spring gear, and provides everything in between.
Tooth count per cog: primary/secondary