Overheating at idle

The reason you don't overheat while in motion is because your water pump is spinning at a higher speed and building pressure plus even 20mph air is enough to be just as good as any fans you could be using. So you have a potential air flow AND sounds like water pump pressure issue. someone pointed out water pump pulley ratio. Look into that.
I solved my problem simply by utilizing a much bigger radiator. 4 row copper/brass didn't work, Big dual 1" aluminum rad helped but still didn't fix problem. Dual 1 1/4" tubes completely solved my problem.