I have been playing around with factory gauges and have come up with interior color differences. Some of the later 74-76 speedometer, tach and combo have no reflective paint or a primer gray. Most of the early 70-73 sliver button have an off white interior.

Center console gauges on the other hand are primer gray or none at all.

What is going to be the best reflective color to use to brighten up the gauges to use standard bulbs or LED bulbs? I am thinking about using chrome spray paint ?

Added a picture of a console gauge for reference.

Chrome paint will make "hot spots" where the light will be especially bright, and others that are especially dim.

White paint is probably your best bet. It should make for a fairly diffuse light.

--DD

Yes I agree that white has always been the best for guages.

Not just any white, paint the inside of the gauge can with the flattest white you can find.

Ok, flat white seems the way to go,