Outer Limits 4x4 Board

hiya all ive found a working water temp guage in my shed tested it in a pot of boiling water and its working find so im gonna wack it in my fj40 the standard guage works (i think) so id rather put the sender elsewhere but icant seem tofind anywhere i was thinking of getting a spot soldered into the bottom radiator pipe where it joins for the heater conection but i dunno if that will giveme a decent reading

lemme know if theres a easy spot i noticed theres like a screw in bung on the head right next to the carby but i wasnt game to undo it incase i shouldnt

cheers
pcman

drill and tap into the thermostat housing?