You guys are all correct, It's an Amco.
As far as proper gauge settings,there isn't one.
I own three of theses babies!,
And my latest acquirment has NO HOLES!
Definely an awsome find!
My next daily driver is going to be an Amco car for I've all the Amco stuffs,
Overriders(Nerf bars)Ft and R)) Walnut shifter with the CORRECT shift pattern on it

of course the center console!
All of these is going into a silver car with WHITE interior!
Going to be F'ugly! I love it!
BTW I've used thoses big switches for powering up my stereo and amp