Hi Mike,
My 2 cents: I would not use the temp gauge location for the fan sender, they are usually placed as close to the lower radiator output (before the water pump) as possible, this is beacuse it gets the fan moving before the block gets too hot.
There are adaptors that you can put in the lower radiator hose for the fan sender, or you could get a "weld in bung" to be soldered/welded into the radiator itself..
If time and budget is of issue, and if your not using a heater on the engine, i would relocate the fan sender to the heater inlet on your waterpump (if it exists on you pump that is)
Good luck!
