That's the thing, I think both our cars are running at the same temp, but our gauges show something different. That's why I said my car has an aftermarket coolant temp sender, maybe it has different resistance values, and shows lower on the gauge than an OEM/NOS temp sender. I bought an NOS temp sender, and I tried to compare the two senders in boiling water with a multi-meter (to get ohm readings) and a meat thermometer (to chart the rising temp and its corresponding ohm reading), and the two senders seem really close to each other value wise, but maybe not. I have to try running the NOS sender one of these days and see where my gauge ends up.
I bought my car with its factory 2 core radiator that was re-cored, and it did an ok job of keeping the car cool, but it would struggle in very heavy traffic. I feel the 3 core was a wise investment, as after sitting in traffic, the car can cool off within a couple miles. Even sitting in traffic, it doesn't get as hot as it used to with the 2 core.