Where is the emergency fuel shut off switch located on a 1987Ford Mustang?

There isn't a single, readily accessible "emergency fuel shut-off switch" like some modern vehicles have as standard equipment on a 1987 Ford Mustang. The fuel system relies on the inertia switch (which cuts off fuel flow in a collision) and the normal operation of the ignition system to control fuel delivery. To stop fuel flow completely in an emergency, you would need to disconnect the fuel pump's electrical power supply or, in more extreme cases, potentially deal with fuel lines (which is extremely dangerous and should only be attempted by someone with mechanical expertise and appropriate safety precautions).