the ac delco's are the ngk they share the same part number ironically i had no problems with the stock or the e3 type. i had my mustang on the dyno about a week ago to get a proper tune for the supercharger. the e3 produced a little more umph but not noticable i would go with the stock ones because they are a good reliable type pluse they are afordable. if you are replacing the wires and coil packs and wanting to get the plugs out of the way i dont blame you because your already there. i agree with you all the way if your there why not. bit of advice use antisease on the plugs do to the heat and cold it will be a pain if the plugs break in the head when repacing them down the road

@Monte07 - You mentioned using E3 plugs, but in a Mustang. I've read people who have used them on GM cars have not been impressed. Good tip about the anti-seize, I use that all the time. FYI - Just because two vendors share the same part number does not mean the part is the same. That's commonly done so the crew at a parts store has an easier time identifying knock-off parts by using the car manufacturer's part number. I know for a time though AC Delco re-branded NGK plugs, at least on our '05 Impala. When I removed the original plugs they said AC Delco on the stem in blue and on the metal banding above the nut it had NGK scribed in them just like the NGK's I was popping into the car.

shouldn't use anti-sieze on the new coated plugs...

The coating is usually silver, sometimes with a greenish or golden tinge to it, it`s not bare metal (dark or black in color)

Why not use anti-seize compound?

1 - you can easily over torque it and deform it without even knowing or even worse pull the aluminum threads right out of the head. Dry and Wet torques are totally different installed values.

2 - if any manages to get to the insulator or tip shorting/misfire will occur.

3 - acts as an insulator and prevents proper heat exchange between plug and head/water jacket.


and it doesn't matter even if you're using a torque wrench to torque them to spec - still do not use anti-sieze or anything on coated plugs...

WET verses DRY thread torque

When applying torque to a dry thread more friction is created. With less friction (wet threads)the threads stretch more before the desired torque is reached.

(example: a dry thread torqued to 10lb ft is 10lb ft, the same thread wet will click the torque wrench at 10lb ft but in fact it is 12 or 13lb ft)

Using thread lube, anti seize, oil or other lubricants all differ in the actual friction loss. One must understand that WET threads require less torque than DRY threads.

Just use stock plugs

You don't need to go colder unless you add a lot of compression or boost

You can believe all that as you want that anti-seize is bad, but I feel you are strongly mistaken. What you listed as reasons not to use it sounds more like urban myth then fact. You are only to use a tiny amount of anti-seize on the threads (a touch of that stuff goes a LONG way). True, if you get some of the stuff on the parts that actually sit in the cylinder, it may misfire, but it won't take long to burn it off.

1. - It's made for applications like this.
2. - Torque is torque. This stuff does not effect the torquing of the plugs, as it is not changing the properties of the metal and because it can spread, it thins/spreads as it's tightened. FYI - I've never used a torque wrench on plugs, just snug them in, works every time.
3. - Not saying everything in the auto parts store is a good idea (I know that bars stop leak for radiator leaks is one of the worst things to put in a car), but they sell anti-seize packets specifically for the person doing spark plugs.

I've changed plugs on my cars, my family's cars and some friend's cars. Got a lot of experience and miles doing these change. Used anti-seize every time I drop new plugs in. ZERO problems.

I know I'm not along in using and believing Anti-Seize works.

it is one of the reasons why i took off my heads on my monte. i noticed a little water disapear and starting to over heat when i didnt check it. when i did the plugs due to a missfire i noticed the threads still in the head and the top half where the plug and the peace to put the plug socket on was snaped when putting little pressure on it. if you use even the malox trick works i mentioned it due to i didnt want any one due what i did spending money on some thing not needed getting the tip out at a machine shop. they didnt re tap the spark hole they said it is a comon thing when not using some thing like it. if three or shops like that say the same thing and rather see and do some thing than taking out a plug they were straight forward. also i always use it on the things i am going to replace if it is going to see insane heat. i dont use it on the calipers due to i want to stop and not have the bolts work lose.

Previous owner of my Grand Am over torqued or screwed up one of the spark plugs. When I changed them for the first time, the part of the plug with the threads were stuck in the head (all the ceramic came out). Dad used and easy out and was able to get it out (2 days we screwed with that). The damage was done by the last owner. Eventually I had a plug coming loose there. One day I resnugged it and the threads were gone (this was 120,000 miles). Hesitant, but I saw some success stories, we re-tapped the head (you lube the tap with oil, tap part way, remove, clean the tap, re-oil, do it again and repeat until done), used a shop vac with a narrow hose to suck debris out, and installed a heli-coil (all with the head on the block). ZERO problems. Car ran great until the head gasket went bad at 180,000. Car is still running today with that heli-coil in it and I've changed those plugs once since that time (I run cheap copper AC Delcos) and it's got 210,000 on it now.

As for Anti-Seize and caliper bolts. That's another myth "Don't use on caliper bolts or lug nuts, it promotes them to spin loose". If this was true, that product would be useless, no one wants something that would cause a nut/bolt to unscrew. Again, I use it on all my lugs on all my cars and the threads of my caliper bolts. Never a problem, always stays tight and best part is, never had an issue taking those items apart for service as a result. Since my first car in 1997, this has been the practice I was taught and stuck with.

I agree with the use of anti seize, taught that way and have never experienced a problem. Except for removing plugs that did not get antisieze

I will say I disagree with this, I would also bet if you set your torque wrench on one setting, and torqued one with that stuff and one dry, that the one with the antisieze would actually be torqued tighter. Not saying that it will or will not be enough to cause damage- just that the torque values will be different.


That's also what I do- it can be practically impossible on certain vehicles to get a torque wrench in there, and I've never had a problem with hand torquing them. If its easy to get to, then sure, why not- but some engines/vehicles make it nearly impossible.

Like the L36 in the F-Body :mad: