SP421 is a PZT2F, SP507 is a PZT14F. I believe the SP507 is 1 heat range hotter, and Ford is recommending it as a replacement back to the beginning. Apparently it's less susceptible to the carbon buildup that causes the plugs to stick.

 

Thanks for the info

maybe I will be able to keep it straight this time around :o

 

So I checked out some pictures of the SP507, then checked fitment for my 07 5.4 Screw. According to Summit, it does not appear the 507 will fit. Rather there was a couple different Champions and they look like what is in there to start...

Am I missing something here? Did they have a fix for the 07's? From reading this thread, it did not appear to be so.

 

The Rock Auto catalog shows the SP507 as the correct plug for the standard but not the flex-fuel 5.4 in 2007. They don't list a Motorcraft plug for the flex-fuel but they do list the same Autolites for both engines. Strange.

The new head design (mid-2008) takes a SP509.

 

The SP507 is a plug that burns hotter then the SP421 (the plug that came in the motor) and is said to help keep the carbon build up down. (thanks to GLC for that info)

 

Thats pretty cool. I'll be sure to find that there tool when I grow the nards to pull the plugs.

 

Which tool?

And the sooner the better (I struggled with that though )

 

I talked to a guy at the factory sometime ago he said ford did a rolling change on the 5.4 3v heads in oct 07 takes a new style plug which is re-gappable and looks like a standard plug and will not get locked in the head from carbon build up, only took them 3 yrs to fix a know design flaw and if u are out of warranty it is your baby to get them changed

 

Thanx for the info sure hope it works

 

Don't worry - either a SP421 or a SP507 will *work* - on any engine with the old style heads, the SP507 is preferred. One way to tell - if the cops are black, it's old style, if the cops are brown, it's new style and takes a SP509.

 

Mine is the Flex-fuel 5.4 as many trucks are here in Missouri. Our last GOV really promoted the E85 since we produce a lot of corn and it was good for the farmers. He even got a law passed that required all gas stations to sell E10 when it was cheaper than regular. It was a glamorous idea for most folks until they realized the cost savings weren't really there per gallon.

Anyway, is the new autolite or champion replacement plug going to eliminate the breakage issue or what? My truck just rolled 25k and I am willing to do the change now if it saves me the pain later on.

 

OK, so what are "cops". I assume you are not referring to the ones with badges.

 

The Champion is a one piece but some have had problems with them and pulled them out. Also, they do not last as long and cost more. Many of us have not had a problem going to 65,000 to 100,000 and going back with Motorcraft. I plan on going to about 90,000 on this, my second set.

 

Coil on plug, perhaps??

 

Yes, COP, Coil on Plug. There are 8 coils for the 5.4.