The distributor was originally on a 12v vehicle (1962)?
112403 was the code for 1959 (and from 1955-2nd series, and most likely after 1959).
On your 1951 truck, you could be 6v or 12v (the distributor with points does not care). If your truck is 12v, you will need a ballast resistor and 12v coil, or a 12v coil with resistance built-in.
