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

That clutch with the little spring on it is the right one to run.
But
Are you saying that your engine is turbo charged?
It would have been nice if you had mentioned that in post #1.

If you put a turkey in the oven,it cooks. If you turn the oven off, and put the oven and the turkey still in it, into a furnace, it will still cook, even tho the oven is off,right?
I'm assuming now that the turbo is under the hood,right? and that the intercooler is up front in the airstream right? And that after the HOT Australian air has passed through the intercooler, now its's really,really HOT, and that really,really HOT air next passes through the rad.It may in fact be so hot, it cannot cool the engine coolant at all, so your engine is cooking in the furnace, called Underhood.
Please tell me I'm wrong and that the intercooler exhaust air is not getting in front of the rad!
..