I have a buddy with a 90 notchback mustang with a 347 and a big vortec pro charger. (694 on pump through an auto.) Anywho, he was replacing the plugs when he pulled out an Autolite racing spark plug box out. I told him to throw those garbage plugs in the trash and get something better. He then mentioned to me how he dynoed and races with these plugs and they work better than most other plugs on the market. What I noticed was how far back the ground strap is from the electrode. I immidiately assumed spark blow out. He said he's never had a problem with them. Despite the distance of the strap, there is still a gap that must be set prior to install. Well, he run 24psi on a procharger with pump/meth so i'm going to assume that the plugs are fine for him.

But, does anyone have any experience with cut-back plugs in our cars?

 

Below is a picture of NGK's racing iridium spark plug for Evo 9's. Hmmm.... I think i'm going to modify my own plugs next time I swap em. (I use standard NGK BR8ES plugs)




These plugs go for nearly $200.00 and are hand build.

 

I also have a foxbody mustang and Autolites are veryy popular in the mustang world, I believe they make the oem ones for Ford also. For my jap evo, I'll run NGK or Denso which is who makes them for the factory also.

To me it looks like the cutback design just makes the spark stay in one place instead of hopping around the surface of the strap and center electrode on a normal standard plug design

 

On paper, a cut back strap allows more flame front which in turn means more power due to a better burn. But, we all know that "on paper" doesn't mean the same thing for all engines. I'm willing to give this a shot next time I have to change my plugs.

 

Just found this during my research....site has tons of good info about plugs and other stuff....Current link should be for the cut plug design

http://www.sparkplugs.com/sparkplug4...Air+Gap&mfid=0

 

O wait my bad wrong design, they do have the cut back design....

http://www.sparkplugs.com/sparkplug4...+ground&mfid=0