I can't seem to find the part number for the revised 1-piece spark plug for use in a late 2008+ 5.4 with the new style heads. My motor was built in August 2008 and has brown boots so I'm 99.9% certain I've got the new style plugs. Can anyone help me out?

 

Did a bit more digging... looks like SP-509 is what I need to get. Does everyone agree?

 

Yes if you have brown coil boots.

 

Thank you sir. Much obliged.

BTW, forgot to ask - is it advisable to replace the coil boots when changing plugs?

 

No, not unless they are damaged.