Swedish 1969 Dart GT + 1964 Dart GT
NOTE: The chip NTE960 used in the IVR (instrument voltage regulator) schematic requires 2 grounds. The wired ground, and a ground at its mounting tab otherwise it will not work. A finned heat sink is a good idea, and i put that in mind when i drew up the schematic, however later on i thought it may not be necessary. Reason being is this part is designed to take "up to" 35V input and then drop it down to a clean oscillation free 5.5 volts output. In this application we are only asking this semiconductor to take 13.5V max and drop it down to 5.5V, and in your application it only needs to do this with 2 instruments, your fuel, and water temp. Your volts gage is already 12V, so its really not working too hard.
To mount it, i would recommend to drill and tap a small hole on a flat spot on your aluminum die cast cluster housing that it can use as a heat sink and a ground. Use the white heatsink grease. I used a 4-40 tap, and a small machine screw for mine.