Mike,
I had my Challenger out today, It was HOT so I had my AC on full blast, I got stuck in rush hour stop and go traffic due to bad lights. It must have been about 4 miles of crawling, overheat your car type 5 mph stopping stuff. Here was a pic of my temp guage. It never moved above this line. I have a 484 cammed 440 with headers and A/C. Idle is set to 750 rpm. 195 degree thermostat. This is when I took this pic. Idling in traffic, with A/C on.
I'm telling you, a 3 core, 26" radiator and fan shroud should fix you up.
Rob