You are wasting your time. Modern parts people barely know how to look up application, most of 'em anyhow. Even back in my day, the catalogs did not show resistor / temp curves for the thermistors.
Get some resistors as Redfish eluded to above and test the gauge "system." Same resistors can check fuel, and if you have it, oil. Here:
That will tell you whether the gauge/ wiring/ IVR as a system is halfway accurate