Cant cool my 5.9 magnum. Radiator size or add one thing else?

I'm not sure "these engines" need to or want to run hotter. It's just the way things are going, historically speaking. We are all struggling with the high cost of gas, and it has been shown that running "Warmer" gets more miles per gallon. The key to successfully running these higher temps in a performance setting,is a rock-solid cooling system, that is well able to deal with the heat.