Thinking of changing the plugs on my 84k 4.6. Ive never had a problem doing spark plugs but these do look a little weird with little boxes screwed on each one.

 

The 4.6L is relatively easy to do. Just make sure you torque them correctly. There have been isolated cases of under torque and blowing them out like the 97-03 motors. Motorcraft plugs and no anti seize always does the trick.