I have found NGK's to be some of the best.

 

Thanks for the useful posts, I think I am going to pick up some NGK Iridium IXs this weekend. Hopefully I will have better luck this time. I only bought the Splitfires because a guy I know had a lightning and sold it before he put these in so he sold them to me for $20. I figured they would be an improvemnet over the stock plugs, but that obviously hasn't been the case. I would say from this experience Splitfires are crap.

 

I use the "V" plugs and they seem to run fine. Just have to replace them more regularly as they don't have the longevity some of the other more specialty plugs have. Double platinum's are also very good. Many manufacturers offer such a plug. Only negative thing I have really heard in the plug area is not to use Bosch Platinums as they don't seem to run well in Mustangs. Don't ask me why but I have heard this in many different forums. I have also heard such plugs as the "iridium" type are a waste of money unless you are at least pushing around the power of a '03 or '04 Cobra, or have some sort of forced induction. For two totally newly designed plugs on the market today, try the following links. Pretty interesting stuff!

www.zex.com
www.e3sparkplugs.com

 

NGK is the way to go...If you call them they will set you up as a dealer so you can order direct...they will even send you a catalog. i go through alot of them with the quad, fiddy, and go kart.

 

AUTOLITE XP 104 IRIDIUM, THE BEST!!!!!

 

Split fires are junk. Motorcrafts are inexpensive and work well in fords. Change them every 10K miles and you should be gtg.