factory temp gauge sender in my 81 malibu was in the stock position (in the head). i made a note of where the temp. was for years. installed a well known mechanical gauge and swapped it into the head and the factory set up was installed in the intake manifold. there was no difference in the readings for each gauge. i watch temps. pretty close all the time. mechanical gauge and factory temp gauge read the same in either position. i have heard that the head position was hotter than the intake position. did not read that way in my application, go figure.