Fuel Gage not displaying properly

Hey Guys,

I've got a 66 Chrysler 300 and I had issues with the fuel gage not displaying the correct amount of fuel. First I thought it was the fuel sending unit as I tested the electrical with a ground wire and that simulated a full tank of fuel but after getting the fuel sender unit replaced it still doesn't display the correct amount of fuel.

Any ideas what I can do ?
Author: Umeracle