Get another starter. I had a special wound hi torque starter that wouldn't start at all. I re-installed my old starter and it worked fine.
Also, plan on converting to 12V. I have done it several times. I can't see your photos from work, but if your stuck is stock, I could rewire it in about an hour. It isn't hard.
I recently had a starter problem with a V8 equipped 48 Ford. I thought the Optima was dying and had been on the shelf for a couple years while I built the truck. I found out after a tow truck ride that the starter was slowly shorting and on the final trip was a dead short. A key indicator of this is the starter housing will be very hot, very quick. The new starter is now click, boom...instant start.
Also, dump the floor starter. Use a solenoid and then any type of ignition switch will work. Again, convert it to 12V ASAP.