where can i install my aftermarket water temperature probe?  

Install it in any engine water passage on the intake or water pump. You can pull the factory sending unit and put it there if the factory guage doesn't work.  

I have had to drill the intake on different occassions to fit an aftermarket unit due to it's larger threads or lack of a hole. When you drill, coat the bit with grease, this will hold MOST of the filings from going into the coolant passage. Do the same thing to the tap when you cut threads.  

Thanks to all of you guys! Right now I'm trying to find a fitting to fit my probe in the 3/8 hole I have on my intake, if not I will have to drill a 1/2 inche hole and tap it.

Hope you enjoy your cars and have a nice ride!! Unfortunately mine is in the garage and I have 4 feet of snow in front of the garage!!  

some may not like the appearance of this,but i used a brass T block,nipple to the manifold, adapter out of the branch of the T,for the probe. then,block 90* and hose nipple for hose to water heater then paint. no drilling, no shavings in your radiator. just another option.