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

Had a nice big answer typed up and my phone lost it.

Short answer: colder is not better (engine wear increases HUGELY on a cold motor). Run a 15 psi cap and let it heat up to 205-210. That is FAR from overheating. remember, boiling point rises as pressure increases, and water expands as it's heated, so with a sealed cooling system, the actual boiling point is well above 212.