jeremy,
Running rich wouldn't make it heat up. Is this engine a stock 6 cylinder, that has never been clarified. Could the previous owner have blocked the vacuum line because the advance unit has a leaky diaphragm? If you worked on the carburetor gaskets, did you reinstall the base gasket with the notch aligned with the hole in the carburetor base...this allows the power valve to function. If it were blocked, the carburetor would run rich.
So far, none of the things being mentioned would be responsible for a immediate increase in operating temperature. Checking the timing with a light would be a pretty good first step.
Stuart
