I've got the 56 grain truck that came to this farm new. It was six volt with the floor starter up until the original engine wore out and I put a 350 in it. I also have a 58 GMC 370 with the original 270 that's 12 volt. I was under the impression it was the first year for 12 volt and a fancy key starter.
I could be all wrong about the 12 volt stuff - I just use them on the farm and pretend to know enough about them to keep them on the road.
