No underdrive pulleys, and have not measured the actual amperage draw on my fan at low/high speeds. Also have not experienced any elevated temperatures in the first 1000 miles of shakedown driving. The highest temps have been coming off the blacktop, dropping to 5-10mph for the last mile of gravel

back to the house, and then not above 210F.
Bulldogcountry1,
Sorry to have gotten so far off track on this thread. I believe you will be just fine with that setup. There are a lot of stand alone fan controls out there, some come with relays and some don't, and the adjustment method varies with the package but you're right on target - that's the way the SPAL package is adjusted. You'll want a relay, and like Jerry said above, switching the ground side is best, with a circuit breaker on the hot feed rather than a fuse. Other than that, you've got lots of information

on sensor location, shroud holes, air flow and control theory to consider as you put your system together. Like Don said so well:
Either return this forum to what was or get the HELL OUT!
Dead!