I did some searches but wanted to get more definite answers.

I've decided on either NGK-TR6 or Autolite 103. Both are pretty cheap plugs. Is one DEFINATELY better than the other?

I've read that theres not a hp difference between regular and iridium but how much longer life can I really expect from the iridiums? Is it along the lines of 4 times longer life? That would then justify the 4x increase in price I guess. Any help would be awesome.

 

Was having problems with the autolite 103's hitting the hedder tube. they are about 1/4 longer. Been using TR-6 with hooker LT's

 

I've had some autolite's they lasted a good 2 days until they cracked. I used Bosh Plats with no success. I'm back to A/C Delco's now. Seems to be doing the job. I'll go with Iridiums when the time and money comes.

 

Ran TR6s a few times...they would get black spots all over, I don't know why. I'm now using Autolite 104s which are a little shorter, and after making 4-5 passes on N2O, they still look perfect.

 

I dont have any experience with Autolite, because i have always run NGK

However i will say this....get the copper ones..............you will have to change them more often, but copper is a better conuctor than iridium...

 

anyone know how longer iridium is supposed to last over the coppers?

 

The Autolite 103 is two steps colder than stock. The TR6 is only one step colder than stock. The equivalent Autolite would be the 104.

I've run the Autolite 103 and 104 plugs with my nitrous applications (up to a 125-shot, or about 625 total HP) for 5 years with no problems. Also used the NGK TR6's with the bolt-on engine and a 125-shot for several years with no problems.