Buy a 6 volt starter.
Bolt it on.
Crank up and go.

There are thousands of 6V starters out there doing just fine on 12 volts. Keep the engine properly tuned so it doesn't require an extended cranking time and your starter will last for years. I seriously doubt the current starter got much, if any "conversion" in the first place.


EDIT: Wait a minute- - - -The 1956 starter will be 12 volt in the first place. Just buy a year-correct starter for a 1956 truck. They're available at Auto Zone, O'Reilly's, NAPA, and just about any local parts store. No point in letting one of the old parts vendors put a vacuum cleaner in your pocket! A 6V starter will have the wrong pitch gear to match the flywheel ring gear on a 56 engine.

Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!