I'm wanting to install A/C in my 1954 3100 and want to utilize an Electric Fan Thermal Switch. My situation is 1) there is only one threaded port and the Temp gauge is using it, 2) The electric fan shroud I'm using covers the entire core of the radiator with less than 3/4" clearance from core. What to do?

I've seen reference to a screw in tee fitting but can not find one. I have heard of (bear with me) slipping the probe into the stream of the upper radiator hose connection. I think this is accomplished by bending the probe feed to a horseshoe bend, then slipping the rad hose over that and clamp the connection as normal. Oh, I've seen reference to a "clamp on" how does that work and look like?

Thanks
Steve