Update,,,
Purchased a temp gun, ran the car at home up to 210 and had my son shooting all the right spots with the gun, on the brass fitting that the sensor is in, on the front of the ali heads and even let the pressure out of the radiator and checked the temp of the water, 170 was the highest reading we could get while the gauge was showing 210, had already replace the sender so the gauge is *ucked yeah ??
Be aware that the IR temp guns should only be used as an indicator as they need to be calibrated for the surfaces they are reading. being off by 40 degrees is unlikely unless you have a bad gun or heavily coated surfaces.
The only way to know for sure what the temp is doing is to used a thermocouple probe installed a closely as possible to the thermostat housing. The probe is then coupled to a digital meter that will read accurately to a 1/10 of a degree or better. They also respond very quickly. I use this method exclusively when chasing temp issues. One can probably get an entire setup for less than 100.00. A lot of digital volt meters now come with this feature/accessory. You can also buy extensions for the probe lead that will allow you to place the meter in the car so you can watch it as you drive. Also make sure you get the correct probe and extension types as there are two different ones. Type J and Type K. Mixing the probes, leads, meter will skew the readings.
In my testing I have found more than one "name brand" gage to be doing exactly what yours appears to be. It is also typical for them to go farther out of whack the warmer the coolant gets.
