Looking at the plug already on the car, and the plug you are holding, look for a light green colour wire, as this is the tacho feed wire, study the two plugs to make sure the car matches the plug on the tacho gauge sets plug, you may well need to remove some terminals with a thin screwdriver or similar and swap around till the car loom plug matches the plug that came with the clocks, you may also need to add the lights green if not in your loom, just take from negative side of the coil and it will work fine, assuming it was from another 4 cylinder car.
tabetha