I ran my 383 this summer with the AC on for a 2 hour drive in 100 % weather .I freaked because it got up to 230(acording to the temp gauge)for a little while,then back down to 200 .I went to my radiator guy thinking I might need a new cap or something and he said even that hot is nothing to really worry about.I have founfd that you just cover the holes in the radiator when COLD and everything is fine.NO MORE