shooper,

Switch to 12v in Chevrolet trucks took place in 1955 2nd series.

It looks like the foot starter was available until 1959. From 1954-1959, the foot starter switch had a side terminal to send 12v to the coil during cranking (lead on 12v systems, the ignition to the coil ran through a ballast resistor).

I do not know if a solenoid driven started was available as an option during those years (or if automatic transmission trucks had a solenoid driven starter as was the case in 1954 6v Hydra-Matic equipped trucks).

I got a dash-mounted ignition switch from Chevy Duty for one of my '54 trucks that has a 1960 12v solenoid-driven starter. The switch is a little loose in the '54's original hole in dash. The part number might have been 53-411. Yes, a 12v solenoid starter must be matched with the appropriate flywheel (I do not know if the teeth were the same on 6v and 12v foot starters/flywheels).

Tim