Thanks for the replies and i will try the suggested tests....The wiring in the car is original but in very good condition and all terminals were cleaned and treated with dielectric before re installation.
JFB05177 - one of my theories is that the gauge ground is NG and I will check that as well as your other suggestions - thank you
Punkdog - it's an original veglia temp gauge with the sensors that others on pantera boards have verified as the most compatible with the gauge. I am also familiar with how to improve the accuracy of the gauge with resistors and tests, but first I need to figure out why it isn't working correctly at all.
To answer your questions, I have no temp switch/EPS nor an MSD nor the original carb (I am running a duraspark ignition and Edelbrock carb).
The wiring is pretty straightforward with the red/black wire to the sensor and the correctly color coded wires to the back of the gauge (which I verified with pics I took upon installation compared to the SOBill wiring pics)
At this point, I need to pull the gauge cluster, get the VOM and see what's up