1942-48 Ford had the option of either electric or wind up and to my knowledge there were no aftermarket clocks. Manufacturers included; George W Borg; Westclox; New Haven and Waltham and possibly some others but I've not seen one in 50+ years of dealing in 41-48 Ford. 6 Volt clocks outnumbered wind up by far as the wind ups in any of the years are rare. The most rare is the Westclox that had the stem come out of the lower bezel and face you as opposed to out the bottom and through the dash plastic. I have on and it's a 47-48. Not for sale but for illustration. Note the speedometer next to it. There is an extra digit on the odometer which I guess was for taxi or police service.