This is not rocket science by any means. Many get anxious because of all the chat regarding the possibilities, with the issue being the original manufacturer of the motorcraft plugs (which I think is federal-mogul), which instead of welding the entire body of the plug together, they 'crimped" the bottom half on. Because of the extended length of the plug, carbon can & does build up on the tip and at that part of the combustion chamber where the plug screws in/protrudes, the carbon binds as you try to unscrew the plug and because of the "crimp" assembly, the bottom half of the plug simply twists off.
Can you really blame Ford, unlikely. Can you blame FM who built the plugs, partially because they will say no-one realized that excessive carbon could build up and factor in gas quality, etc, etc....
So, if you have 50k miles or more, do (or have a mech do) a fuel injection cleaning service, have an extraction tool handy (about $50 online) then give it a try. If it's too much then drag it to a mechanic.
and yes, without breaking any plugs, including soak time, it took me 4 hours...so plan on the better part of a day.
Member: Never trust a person over 40 who drives a Chevy club
Flatheads ain't so bad!
Certified backyard mechanic I & II