1 3/4" to the back of the housing, 2" to the center of the two nuts for mounting from the back of the face. 1 3/4" between the two mounting studs across the back of the case. 2 1/4" diameter of the case. Think that is everything.
Thanks so much Curt, that helps a lot.
That will work great for what I have in mind.
Now I just need to find an electric oil pressure gauge the same size and look as the Tach LOL.