Kevin
I thought I remembered, but I had to look in my parts book, and now I'm not sure because it only goes to 1957.
From 55(2) til 57, the starters on the V8 were key actuated, while the on the 6 cylinder, they were foot operated. I kind of remember that the 58 may have been the point where the 6 went to a key and solenoid starter, but I could be wrong. That might explain why you have the factory plug in the hole.
What will tell you what the truck originally had in it is the VIN. If it starts with a V, it originally had a V8, if it doesn't, it originally had a 6.
Hope this helps.
