Temp sensor size?

Is this mechanical gauge or electrical?

Mechanical gauges are a "whole different"

Back in the day, they were "somewhat" standard, and you could buy different sized bushings. The nut and sender with the gauge are proprietary

If this is an electric gauge you MAY be able to find a different sender that will work. Who made this "gauge pod?" Is this some nondescript china, or Autometer or what?

Bosch gauges. Mechanical.