I ended up going with one. How correct are they? I have it all hooked up and am programming it. Tell me if this is right. With the car running say my mechanical gauge says 180* ( mounted in the drivers head) . The Dakota unit reads 170* I'm using there sensor so theres no calibration. It' says its 10* off. Now I have a $100 IR temp gun and these are my readings. The sensor is in the manifold. When the dakota unit reads 180* my temp gun reads 182* shooting it at the radiator right where the hose connects to the top. I would think that would be a correct reading, but the temp gauge is in the head. It's normaly HOTTER in the head. Could the gauge be off that much?

Yep
I once had a fan switch in the passenger head of the 59's 454.
The fans would never shut off.
When this same switch is put in the manifold, it started working correctly.

But----let us know how this all works out for you
I'm considering getting one for my 59---as I am now on my 3rd fan switch.
I want my fans to come on @ 225 and go off @ 210. (or thereabouts)

Finding a switch that will do this seems to be an excersise in futility.

And with my Dakota gages----I think all I need to do, is to tap into the temp sensor.

Bryan

I ended up moving my mechanical gauge in the manifold under the water neck. I tapped the Dakota sensor is just to the right of that in the manifold with a 1/4NPT tap. Theres a spot on the manifold made for it. The temps are within 4* now. I did some tests. The controller lets you set the on-off temps for both fans then test them before the car even starts. It's pretty neat. Theres a small pod on the side of the unit that you turn and watch the digital temp go up. When it hits your set points the fans come on , then turn it backwards and the go off. Really neat. I don't have the radiator yet so I cant tell you how it works in the real world yet.

I have a 180*stat and the settings are
Fan1 on at 195* off at 185*
Fan2 on at 200* off at 190*