blue plug

[jaspermaggie]

I was looking at my plug autolite 3923 and the tip is blue about 1/8 - 1/4. I know it is getting hot should I change. I went one colder but it is still projected. I tried a race plug and it was to cold. I was recomended by trickflow the fr5 or 2924 for the street. I run a 125nos shot with 4* out the motor has 10.3 to 1. What would you do.

[jaspermaggie]

would an autolite 3935 be colder than a 3923?

[chpcamaro]

i would go with ngk plugs that way you will melt the plug tip before a piston just a thought

check this out http://www.dragstuff.com/techarticles/s ... rence.html

[Chevyfireball]

By the tip, do you mean the electrode or the ground strap? If its the ground strap, thats showing you where the heat is reaching and you can tell how your timing is. Mike Canter has a tech article on here somewhere that explains it all... real good reading.

[ojh]

The autolite 3920 series is a projected tip, ok for daily drivers but treacherous for a hot rod esp w/nitrous. replace them with AR3933 (same heat range) and see if that doesn't make better sense to you after a hard pass.