Go to Ack's FAQ and find the wiring diagrams for the vehicle, you appear to have multiple issues.
Turn signals - assuming you haven't tried to fit LED lamps as a part of your restoration, the turn signal system uses a rapid flash rate to alert you to a failed bulb, so start by leaving the engine idling with the left turn signal on and walk around the car to see which light is out, and if they're all working, verify that the correct bulb has been fitted.
Gas gauge - the gas gauge is grounded via the sender in the fuel tank - check to make sure there isn't a short circuit somewhere behind there.
The tachometer is most likely an internal fault in the instrument itself - it gets a pulse signal from the ignition and reports what it sees
Turn signals - assuming you haven't tried to fit LED lamps as a part of your restoration, the turn signal system uses a rapid flash rate to alert you to a failed bulb, so start by leaving the engine idling with the left turn signal on and walk around the car to see which light is out, and if they're all working, verify that the correct bulb has been fitted.
Gas gauge - the gas gauge is grounded via the sender in the fuel tank - check to make sure there isn't a short circuit somewhere behind there.
The tachometer is most likely an internal fault in the instrument itself - it gets a pulse signal from the ignition and reports what it sees