I ran a 6 blade AC water pump on the 440 that used to be in my GTX for about 14 years. The first one had 93,000 miles on it when I installed it, it started leaking about 10 years later. I replaced it with another 6 blade from the parts store.

I always used non/ac pulleys.

In 14 years, many of which were daily driven (for a few years the GTX was my only transportation) the only heating problems I ever had were due to either me not using the fan shroud, or the radiator being clogged. Even when the first water pump leaked, it did not overheat.

So I guess I don't agree with the whole diagnosis, but good luck with it nonetheless.