The gauge is a Sunpro CP8084. The faceplate is held on by 2 tiny screws. I removed the faceplate, and used it to locate the holes at the base of the backing plate. For the backing plate, I used the ammeter as a template. I haven't finished trimming it yet. It will be mounted behind the voltmeter faceplate, just to fill the gap that the ammeter filled. I may paint the edge of the voltmeter faceplate to make it blend in better with the backing plate.
The bolts are the same distance apart as the ammeter, so it slides into place. They are longer, and I will probably have to use some nuts to space the voltmeter in the gauge pod, since it will just fall in too deep, and sits much lower in the pod. That's not an issue, though.
I will also paint the needle with some Testors model paint in the correct orange. I may hit all the needles just to be sure that they all match.
So, what do you think?