Originally Posted by 1DrunkCat
Gap specs are .049-053 in the 2011 Mustang shop manual for the SP-520. Like you, I checked the gaps on my plugs before I changed them this morning, and they were all gapped at .052. Strange. I got my plugs from Rock Auto, not that it should make a difference in pre-gapped specs.
I don't think it makes a dimes worth of difference between .050 and .054 in the plug gaps on the plugs in these cars, as long as they are uniformly the same gap. But, it does say clearly on the box not to change the gap on these plugs. That's why I'm wondering if Ford/Motorcraft changed the gap specs for these plugs. I'm hoping that if anyone has heard this, they will post here. I just find it strange that these were gapped the same as the Autolite plugs for this car.