Temp sensor size?

I got a new gauge pod for my car but the sensor on the temperature gauge is too big. The sensor part below the threaded portion will not even fit in the hole. Am I completely missing something or do I need to get a different gauge? This is on a small block if that matters.
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?