Re: Much harder with an alternator
It was usually easier to flip the car, in a 1964 Mini/Morris almost nothing was polarity-sensitive. Early car radios could sometimes be switched (I remember taking my Dad's old Pye radio and switching it to go in my Mum's Morris Minor) but as -ve-earth-only car radios became more popular in the 1970s there were plenty of magazine articles about how to swap the car to -ve earth. Reverse the starter motor wires, some connection changes on the regulator, and 'flash' the dynamo to change the residual magnetism, that was about it. You might have to swap the heater fan motor wires, if your car had such a luxury. Avoided all the problems with shims, isolating cases, stray wires, etc.