Best place to put Temp probe

Even if not "exact" if you put it in the block drain, (if you can reach it with your mechanical gauge lead that is) it will be a steady deal, you will know where you "normally" read and if it deviates from what your established "normal" is theres still something wrong somewhere in the system....

I put one in my Durango and I don't know if it's how I mounted it or if the gauge is a little out of whack, but with new 195 thermostat (changed a couple of times since aftermarket gauge out in) and everything full I normally read 180, have never seen the 195-200 id expect out of a 360 mag. Occasionally 190 towing and 95* out.... .
I had to screw a pipe extension into where the heater hose returns to the beer barrel intake to get clearance around the beer barrel itself, it's about 4" above the manifold surface and in one side of a "tee". The heater hose that belongs at that port in the other leg of the "tee". The dash gauge still reads off it's stock sensor in it's stock location and the same as always when all is well. Again no numbers on factory gauge. Just a few needle widths short of "straight up".