I got ‘17 5.0 .
original Plugs Motorcraft SP-519 .I believe iridium.
Ford replaced them with SP-548 Platinum
Manual say the gap .049-.053
They came all with roughly with . 049 pre gapped.
I have seen some recommend to gap at 0.44-0.46 for some reason. What benefit does it give?
Do I just pop them in or regap to tighter one?
Also Anti-Seize or Not ?

 

On my 2015, 5.0, I put iridium plugs in, only checked the gap, which averaged 0.049 to 0.050. Also used anti-seize. The issue with, especially plugs with very small diameter electrodes (like iridium), regapping can damage the tip of the electrode. I pulled a few plugs after 60k and they still gap checked in spec and looked clean as could be. So put them back in. Traded off for a 2020 a few weeks later.

 

Thank you. Replaced them all last night. Seems like running a tab better

 

They always do just like running the valves on the racecar. Just don't look at your trap speeds afterwards. Really has something to say about the reliability of the butt dyno.