This is where the "Fox Body" Mustang got it's name. I also forgot to metion the Zephyr, and a few Lincoln's too. Cougar's, Capri's, and some Wagon versions of these too.
Here's a partial list:
http://www.ford-fox.org/faq.php?myfa...s=Fox+vehicles
Ford used that chassis on a TON of vehicles. You'll find "extra" plugs in your wiring harness for that reason too. That particular plug might not be used on your application, but a Turbo Coupe T-Bird might have needed it.