Cooling problems

That fan is probably one of your issues. A mechanical fan with a shroud would do way better. If you're set on electric fans, look at the Contour/ Taurus fans that people on this site have had good luck with. Check Rock Auto for good pricing. That upper hose disrupts flow. Does the lower hose have a spring in it to keep it from sucking shut when you drive it. Get one from a Mustang parts supplier. You need to put the thermostat in a pot of water, and heat it up to verify opening temps. Buy a meat thermometer at the grocery store to test. I had some that didn't work properly.