Is there a way to convert a Crosley to a twelve volt system?.

In your question for 12 volts if you want to run the water pump in the original fashion, I used a 55 chevy generator with power steering. This generator ran the power steering pump from the rear. I drilled the shaft for the water pump coupling. the generator is a little larger and requires grinding the mounting bracket to get the shaft to center with the water pump. You will need to change the voltage regulator to the 12 volt one. Of course the regular things such as reducing the voltage for the fuel gauge is required, and changing bulbs etc.

Just install 12 volt fields from a 12 volt autolite generator into the original Crosley generator. then install a 12 volt voltage regulator. you do not have to reduce the voltage to the gas gauge, just change you bulbs. To make sure your gauges read the correct way, be sure to buy a voltage regulator that is either neg. or pos. ground. then you just have to polarize the voltage regulator for pos. ground. (all the old Chryslers from 56 to 60 used autolite generators. The fields are still available from a good generator shop.

I've found that a properly tuned engine starts so easy-cranks fast & all of the stock 6-volt parts are available--Why waste $$ converting to 12 volts??