Pull the negative battery cable off the negative terminal after unbolting the nut fastening the C-clamp to the terminal. Do the same for the positive, but make certain you remove the negative cable first in order to avoid a shock. Unthread the wing nuts holding the battery in the battery mount cage. Remove the 6-volt battery. Grind the battery mount off the frame of the tractor. Weld the 12-volt battery mount in its place. Place the 12-volt battery on the mount and secure the cage around it.
Remove the two positive wires from the generator by unscrewing the nuts on the generator's terminals. Unbolt the generator from the generator mount. Grind the generator mount off the tractor's frame and weld the alternator/regulator mount in the same location. Unthread the bolt holding the wire running from the coil to the regulator. Unbolt the regulator from its mount. Grind off the mount off the tractor.
Attach the wire running from the coil to the 12-volt alternator's terminal with a nut. Run the positive wire from the battery to the alternator.
Unscrew the light casings, remove the 6-volt bulbs by pushing in and twisting them one-quarter turn counter clockwise. Unthread the screws that attach the light assemblies to the light housings and replace the assemblies with with your 12-volt assemblies. Put in the 12-volt lights and replace the light covers. Replace the 6-volt fuses with 12-volt fuses by hand.
Connect the negative battery cable to the 12-volt battery's negative terminal.