What Kinda Spark Plugs ?
 

what kind of spark plugs are the best for 4.6 ltr
what do most people use. what to set the gap on
motorcraft - autolite - ngk ect.

NGK.....they are already pregapped

Autolite coppers. gapped at .054. I belive its 103 or 106. double check on the number. cheaper than NGKs and ive heard of far far far less problems with them. I run autolites personally over NGK.

I ran autolite copper for awhile didnt like them at all didnt last long either. NGK TR-6 or part# NGK-4177 are also copper fairly cheap as well.

they arent made for longevity. if you want longevity you get platinum.

Platnum sucks what milage do you get on your autolites?

exactly, thats why no one runs platinums who mods their mustangs. lol Im at 10k and running strong.

TR55's for copper or TR55GP's for platinum, they are pregapped at .58 but i still regap to .45. For some reason, my car doesn't like that big of a gap.
I thought the TR6 is a colder plug for power adders?

TR-6 are one step colder but you cant tell really

autolite coppers, 103 I think... been a while since I had to remember. Change em' every 15K miles like back in the old days and you'll have great results.

Ngk Tr6 Ftw!!!

Autolite coppers hands down. NEVER HAD A PROBLEM....The only thing that sucks is you have to change them every 20k miles .

If you get NGK TR6's don't try to gap them at .054....they aren't made to be gapped like that....they come pre-gapped at like .035 and shouldn't be gapped more than .008.

"According to NGK you should not open or close the gap that the plug is designed for, more than .008" Example: TR6 is designed for .035" gap. So you could if just running N/A gap up to .043". NGK advises when you go over the .008" that the ground strap is no longer parallel with the center electrode and can/will result in poor performance."