Hi lasts. I am having the same issue. I installed a new 3 core Brass and copper radiator, A new fan clutch, new radiator hoses,180 Thermostat, New sending unit and my temp gauge is still reading 210+ We checked with a infrared thermometer and it shows 180. What resistor do I need and does it go on the gauge? My engine is a 350 that has been rebuilt with auto trans. I also noticed this engine has 2 sending units. 1 on each head. We unplugged the passenger side and it didn't change the gauge. Later found it was for TCS for emmisions.