Have mixed opinions on this.
Pro block heater. You do live in Chicago. You get a lot of snow and ice, and winter temps can get down to - 20, -30f. It would be easier on the engine during morning warmups with a block heater. Might be nice to have. Anchorage, or Fairbanks, Alaska where it gets down to 40 or 50 below;
oil gels, and gasoline won't ignite because it's too cold, that's a different story.
Against. Like MrFixit suggested, use a 5W30
synthetic in the winter, and you shouldn't need it. Just let the engine run a little, and let it begin warming up before driving. Hey, it's a Ford, not some tempermental British, French, or Italian engine. People drive Fords year round in Chicago, right?