I bought a set of Autolite 3923 for my AFR heads. My previous plugs were TR6, but those AFRs need gasket plugs. Anyway I wanted to know how many people use the 3923. I write on the search engine of LT1 / LT4 Engine Tech "3923" and found only 2 (two) threads. These plugs aren't for NA applications? Only for FI ???

 

Any reply ?

 

That's not the plug recommended in the Spark Plug Reference guide in the N2O Tech forum.

 

Yes I saw its written Autolite 3910. I did a search and couldn't find whats the difference. They are cold plugs, thats all I know.