If the starter in the '46 is good then just use it. The wireing in a 6v starter is harvier than a 12v and it will really wind the motor over, even with more zing that the 12v starter will. And like every one has noted the 6v and 12v gears are incompatable so if you use a 12v starter, you need a 12v ring gear and the same for the 6v system.
DG


Denny G
Sandwich, IL