Had an overheating 440 and did exactly that. It helped a little but in my case at least didn't solve the underlying problem (TQ). Fixed that and now the car runs nice and cool even while idling in traffic with a/c running at full blast.
Obviously I didn't swap the stock unit back in just to check how much of a difference the FlowKooler makes. It's well made though and the curved blades look like they're an improvement over the Mopar pump design.