Electric fan vs. underdrive pulleys power/benefits


New Member
Aug 13, 2005
My mostly stock '90 5.0 is currently eqquipped with one of those rather noisy Flex-A-Lite flex fans. For about the same money I can replace it with a new electric fan and thermo-switch kit or a new stock clutch fan with March Power and Amp pulleys. Which combo would free up the most power? Despite test, most people agree pulleys make a descent gain for the money and the stock fan is probably more efficent than the flex fan. On the other hand, the electric fan is even more efficient and takes the weight off the water pump. I'd rather not pair pulleys with and electric fan for fear of charging issues. The car has no cooling issues to speak off (other than sounding like a Hoover on hard accel.). Any thoughts on which set-up is more benificial?
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i hjave pulleys and a electric fan on my 351w in my car and i havent had any charging issuses at all. I don'y lik seeing my car hit 210 degrees but that has only happened a few times in the worst of stop and go traffic on the hottest of aug summer days.
I also run underdrive pulleys with an SN95 electric fan with no issues.

I run a 130A alt from a '95 GT along with an ASP 1 7/8" Overdrive alt pulley. At idle with everything on i still put out over 12 volts. Just off idle i get instant 14.0 volts.

A fresh coolant flush and water wetter got rid of any cooling probs as well. I run 188* solid on 100 degree days with the underdrive pulleys.

Oh and since i did it all at the same time, it was a HUGE seat of the pants improvement!