Jerry,
At one time back in the 1960's through the early 1980's Ford always seemed to have a lot of different parts for the same cars??? I recall that when the went to the electronic ignitions back in the 1970's they had an external box (outside the distributor) that were all the same aluminum box except there the wires came out had a colored plastic gromet....If you were replacing the ignition box, you had to be sure to replace it with one that had the same color gromet and hope that if somone changed it before you that they where aware of the difference and put the proper box on.
Years ago, my oldest daughter had an old Ford EXP and the ignition went out. Testing indicated that the pickup in the distributor was bad so I replaced that, but it still would not start. Further testing indicated the the external electronic ignition box was bad. When I went to the parts store is when I found out about the gromet color. The parts guy looked up the proper one in the book and it turns out the old one was not the proper unit??
That's really bad when they make different parts with such minor visable differences and just add to the confusion..:angry:
....Rich