on the autolite 3923's, arnt the copper and platinum basicly the same plug except for what the tip is made of? from what i have read, the platinumis the same thing, justholds up and lasts longer, is this correct?i have read others on this site say that the platinums gave them a boost and then others say they sucked. i put 3923 platinums in mine just becausei had a rebate and the price came out to the same as the copper ones so i thought what the hell. didnt really notice a difference from the 5224's that were in there tho.

 

The copper ones are apparently way better. Copper is a lot more conductive therefor giving you a better spark but won't last as long. But id rather have a good running engine than longer lasting plugs. The plats probably change the heat range.... I am sure the the price you pay for plats you can probably change out the copper ones, again so it kind of evens out.

 

Do the 3923's fit the 3.9 aswell?

I have used bosch plats in my mazda (before my dak) and ya know i didnt notice a difference. If they arent better than the coppers id just get the coppers and change them a bit more offten.

 

I just installed the 5224's I will have to tell you guys if i notice a different..

 

I always use NGK V-power

 

So do most rice rockets...

 

LOL, I got them in my truck too but I also truck NGK for my dirtbike, they are one of the better spark plugs so why not in my truck too!

 

I see alot of talk about the 3923's but if you go to the partsamerica website they only autolites they list for the 4.7 end in 5224, the prefix chsnging for the differnt types. Is there a difference between the copper 3923 and copper 5224??

 

the 3923's are one heat range cooler than the 5224's...dyno tests have shown 4-5 horsepower more with 3923's, although i didnt really notice a difference myself

 

I put Bosch plugsin my 04 4.7, and it didn't run right. I took them out and took them back to Auto Zone, and was amazed they refunded them. I got the Champions that are on the underhood sticker, "the same as what I took out", and it runs perfect, so I guess they only like certain plugs ?