I'm returning my 70 back from a 30 years sleep but I've an issue with the dash gauges. This car has rally dash gauges but as soon as I turn the ignition switch ON the gauges goes crazy, all they (oil, gas, temperature) starts shaking and all goes immediately to the right so I'm not really sure where should I start looking into.
Sounds like you have a few bad grounds they get corroded from sitting in a damp climate, also check you starter wires they can be lose. the gauge are probably find. I'm sure someone else will chime in.
The gauge pods ground to each other through a strap in the bolts on the back. I had mine go crazy and I cleaned and added an extra ground to the chassis for the pod. But bad grounds do crazy things.