How to disconnect the speedometer cable? 1972 Ranchero

If you have not already done so, it will be easier to remove the instrument cluster by first removing the bezel. The screws retaining the cluster should be easy to find. Once the cluster is loose, you should have enough room to pull it forward and see the cable running to the back of the speedometer. Press the flat surfaces on the quick connect assembly. Pull away from speedo.
Jon