1. We have had members who have had very poor results with Autolite plugs in both 4.6's and 5.4's. They may run okay on installation, but they deteriorate quickly. They may be made by Honeywell, as are Motorcrafts, but they are not made to Ford specs and among other things, the heat range may not be right.

2. The 4.6 and 5.4 2 valve heads only had 4 threads till late 03. There are many instances of plugs loosening and blowing out when installed as per the manual. Go take a look at blownoutsparkplug.com - he is a master Ford tech and has determined that if you use NO antiseize and torque them to 28 ft/lb they do not blow out. If you use the recommended Motorcraft plugs, antiseize is not needed, because the threads are nickel plated. This takes care of the dissimilar metal issue.

 

I would stick with motorcraft in a ford delco in a chevy and uncle bens in jap POS

 

We are refering to these engines and these only, run any plug you want to, - it's your engine right

What repair manual recommends anti-seize on these plugs? Also, where does it say to run plugs that don't meet or exceed spec. The AL 103's/ 104's don't, but yea, you can run them for awhile. - If your lucky.

I bet you'll find out what the deal is, in the near future.

 

Haynes.

Last I checked nickel was dissimilar to aluminum. Hell, even the anti-sieze is nickel-based