Most everything I would advise has been covered, manifold vac. advance, hot idle compensator (by the way, if you keep an eye on eBay, you can score one of these for reasonable money sometimes, and I actually have a few in surplus, because they are hard to get when you need one), Thermocure, etc.
I know the general sentiment is that thermostats cannot fix an overheating problem, and I took that fact for granted as well. I was reading somewhere a comment about using a high-flow thermostat (one with three crossbars on the front instead of two). I really wasn’t familiar with those, and figured all thermostats were the same other than temp ratings and quality of manufacture. The person was insistent that these was the only way to fly, and made a huge difference. I was building an engine at the time and needed to replace my intake manifold gaskets on another car, so I figured I’d just try a couple of these for the heck of it. My car with the manifold gasket leak had always run on the verge of hot. In the summer, the stock temp gauge would creep up to the P in TEMP more frequently than I liked. In IR thermometer said I was about 212-220* at my upper radiator hose. (By the way, this is a concours, low-miles C-code 66 coupe, automatic, no A/C, had Ford 195* factory thermostat).
I used the Mr. Gasket 4364 180* High Performance Thermostat:
Keep in mind that this was the only variable I changed. For the first time ever, my car runs very cool, arguably too much so. The gauge never even reaches the half-way mark, and generally hangs out between T and E of TEMP. I estimate this has reduced my engine temps by at least 15*, maybe 20*, and I’d have never thought it could.
I thought about all the overheating threads that come up in the forum and I believe that this should at least be included in one’s quest to cool things down. If it works like it did for me, it really has to help.