My 87' 302 call's for a stock plug gap of .044 w/ stock ignition system components. However for 302's only a few years newer, stock plug gap increases to .054 w/ stock ignition system components.

The engines use identical ignition components, down to the last part #"s & Identical spark plugs. Why the .010 difference in plug gap?

If you can answer that, you may have "all" my rep votes. I've been trying to find out how/why for years!

Well, how about 1/2 my rep votes?..........You will definitely a rep vote out of it!!!

 

I would go with it being for emissions sake??? Chrysler did the same thing for the PT Cruiser engine ..... but as a TSB for all model years .... so I have now idea what I should gap at for that car!

 

It was 92 that the gap increased IIRC and I think ford did it to increase some HP.

 

A wider gap is generally used to fire a leaner mixture.