Do you want to remove just the gauge cluster or the entire dash? The gauge cluster is removed by removing the face plate behind the steering wheel. Several phillips type trim screws. Be careful when removing it as it will scratch the steering column if you are not extremely careful. I have gotten to where I drop the steering column to avoid this as I have repainted it more than once

Once the face plate is off be extremely careful of the gauge cluster itself. Many of them have become very brittle with heat over time and can literally crumble in your hands. Autometer and most other gauge companies will have the size you need. 2 1/8 or 2 1/16 if I remember right. The headlight switch must be removed before anything else. reach under and find the release button on the side of the switch behind the panel. push on it as you pull the headlight switch out at the same time. Not an easy task I might add as you will probably be laying upside down with your butt over your ears and your feet in the headliner

Hope this helps, Keith