A few things here..
-Personally, I don't feel 210-220 is too hot. I have a few muscle cars and 220 puts the needle straight up and down on the factory gauge, which would suggest that the factory felt that temp was ok.
-If you want to have better cooling, get rid of the 4 core rad. Yes, I know it sucks to shell out $500 for another rad. But, the key to cooling is surface area. Get a 2 core rad with 1.25" tubes. That way you have more fluid being exposed to cooling air flow. You will see a big difference.
-Are you running a 160 or 180 thermostat? If you have a 180, try switching to 160. This will allow water to start flowing at a lower temp and begin the cooling process sooner.
-How is your fuel to air mixture? Dropping more fuel into the cylinder which causes a hotter burn. You can drop 10 degrees just with a carb adjustment.
