Cooling issues 69 Dart GTS 340

Maybe I missed it somewhere you mentioned 7 blade fan. Is this on a clutch or flex fan? If on a clutch make sure your using a heavy duty clutch as the resistance of the 7blades over a 5 blade fan normally used with the std duty clutch causes the clutch to slip to much at low speeds. The results will be heating up gradually at idle and low speeds. Also as mentioned make sure there is a shroud installed.