Tony,
If you are going to convert to 12V and fit an alternator, can I suggest that you also fit an electronic distributor;
http://www.walcks4wd.com/Product/Dis...Electroni/2667
Below are grainy photos showing a RHD Jeep that I rebuilt for a customer years ago and if you look carefully you can see the alternator. I machined a smaller diameter 'B' section pulley to fit to this alternator to slightly increase the speed/charging rate to compensate for shorter drive time for this jeep. I also fitted a red coloured charge indicator light in the dashboard.
Happy deliberations.
Cheers
John Wilson