Do you guys recommend anti-seize on the spark plug threads?

If so what do you reduce the torque to? Or do you use the specification in the shop manual?

No

yes I would use it on all the engine bolts.

MOST DEFINITELY. Any anti sieze is better than none. We use both copper slip or a high nickel high temp anti sieze on our plugs.

Just be sure to torque them up.

A little goes a long way.

Used it for years...

Yes

Unless you plan the plugs to be in there for more than 5 years, there is probably no purpose to it.

I would not recommend it. There is no reason for it.
It is not as conductive as the metal on metal contact and already that is bad news.
Aren't there enough P0300 codes out there already?

I agree with your initial assessment of conductivity... however, I've never seen an issue from using the stuff on plugs... regardless of application. However I have seen seized plugs.

if you try reading plugs the anti seize might give you another false indication. In that case use high presssure grease. Something like wheel bearing grease. In any event. it only takes a dab, don't "more is better" it. It is standard pratice to use Something on an aluminum head.
A little trick I heard from mech who has been around, better to under torque the spark plugs than over tighten them. His question, "have you ever found a bolt loose when removing it?"
Alloy heads will strip out threads, will dissolve, keep your anti freeze feesh and think of the head threads as being like cold butter.

NGK, Denso plugs are usually made in nickel-cad plating anyways which will protect against seizing. This cant be said for most plugs manufactured in the US. I have never heard of any Ill effects of using antiseize, specially not when it comes to reading the plugs.

We had / have a misfire detection system within our F1 & old CART ECU's, we couldnt measure a difference between a bare plug & one that is coated with differnet types of compunds. Maybe it had to do with the amount being applied to the threads.

You only need a slight amount on the threads, imagine a uncooked grain of rice worth of compound. The way you are describing it sounds as if your marinating the spark plug in anti-sieze.

As of late two manufactures have come out and stated anti-seize shouldn't be employed on spark plug threads. Porsche states that conductivity problems might occur. GM appears to be concerned with over torque. Last time I checked NGK claims that their thread manufacturing process mitigates seizing issues and recommends against the use of anti-seize.

Wurth's sells a copper loaded anti-seize compound for this purpose with the claim of good conductivity. With the P300 problems I can understand the concern!

Does anyone know what the rule of thumb for the reduction in torque when anti-seize is used on threads?

hmm I wonder if there is relation between the use of this and P300 codes.

How do you know if you received a PO300 code? Via check engine light? I have tried 3 different plug types to date, while swapping the stockers in between.

The whole time I have used both anti-sieze & copperslip.

No CEL to date.

Torque reduction? Hell, if the threads are bone dry, you potentially will receive a false torque reading due to binding.....WTF

Good luck with what you decide.