All I can tell you is I have had the Black Magic fan for several years without any problems with cooling and over 300 HP.
I have run this fan with the factory radiator and water pump and also with an alum radiator and an Edelbrock water pump. With and without A/C...never a problem with cooling, but improved cooling with the alum radiator and Edelbrock pump and A/C delete.
IMHO it is a good mod, cleans up the engine compartment, frees up some HP, and good cooling.
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fordgasm
CLICK HERE to see my 87 GT