You don't want to move the trans coolers, it needs to be up front for the transmissions sake. I have had the same high engine temp problem with my 360 B'cuda. I have a 904 with a 9.5" Dynamic converter (more heat). I have made 2 changes this month that have cooled things down considerably. First, I found a deep trans pan on Egag that has an extra quart capacity AND cooling tubes that run through the pan, front to back. Literature that came with the pan says it reduces trans temp 20 to 50 degrees. So you are getting rid of some trans heat at the source before it ever gets to the radiator and coolers out front. Second, I changed from 20w50 diesel motor oil to 10w30 Pennzoil and added a bottle of ZDDPlus additive. Oil pressure is still good, and the thinner oil and lower pressure dropped the engine temps further. I had it out for a run last weekend in 90*+ weather, and it did not go past 2/3 to H. Now to fix my fuel delivery problems

EDIT. Also, when sitting in traffic, shift to neutral. The idle will pick up slightly, and the engine will stop lugging against the converter/trans. Both should help cooling at least a little.