Ok. Here's my conclusion on the "over heating issue".
First of all, the sending unit placement is on the intake. Horrible design. And quite honestly, I've never seen an intake with water ducts built into it, but I'm not an expert.
The sending unit, again, heated up and turned on the light. So, I took a meat thermometer, pulled off the radiator cap, and stuck it in the water. 140 degrees. Took it out, drove for a while, came back in, test again: 148 degrees.
Now, keep in mind, this is with a new water pump, a re-cored radiator, a new sending unit, and with the thermostat taken out. Also worth noting, no smoke, no bubbles, and no misses in the engine.
One person posted it could be because it's running "lean". Not sure what to test there.
From here, I'm putting in a manual guage to monitor the temperature, just to be done with it.
Next I'll be asking about how to rebuild a valve control assembly, but that coming later.
Thanks for everyone's help and patience. Great site, get advice.