Help with Cooling Issue Please

FWIW, I had the same issues with my 440 E-body, hot day, lotsa idling, gauge would creep up well past 210. I had a shroud, flex fan, aluminum rad, good hoses, new gauges. Some reading around the 'net talked about straight water being more effective at cooling, so I gave it a try with a 25/75 antifreeze/water mixture, and a bottle of the Water Wetter thrown in to boot. Actually did make a difference. I didn't try straight water before I sold the car. Since you live in Florida, you probably don't need the antifreeze, and the Water Wetter is supposed to provide lubrication, etc.

Just my 2C worth, and I hope I don't start a sh#tst0rm with this comment.