the speedometer and the tachometer are removable, the other gauges are fixed with nuts and a bracket from behind each gauge, they are very tight. use the right tools. Disconnect the battery before inserting a metal tool behind the gauges, it's easy to cause a massive short circuit.

To remove the speedometer or tachometer:gently Push in and turn the gauge anti-clockwise by the black edges. you will feel it "releasing" from its notches. then you can pull it out carefully because it comes out with all the wires connected.

these wires are very delicate, easy tocause damages, so be gentle and don't twist them once out. If you want to completely remove the speedo or tach, then make a sketch/drawing to remember where each wire and bulb came from, don't rely on memory.

the two holes are large enough to get your hand behind the dash, where you can access the other 4 gauges with a mirror and flashlight, again, make sure you write down notes and make drawings, a wrong re-connection can fry the wiring harness forever. Caution and slow, methodical going is the trick.

Jose