Spark Plugs

[JimNolan]

Guys,
   I got a question. My Edelbrock 428CJ heads call for the RC12YC spark plug. I've had the plugs out to check them but advice has been with the bad gas color can't be considered when looking at a plug any more. All I know is they are light brown in color.
   As some of you know when my engine warms up during drag racing I've been having a fuel starvation problem. As one guy put it " don't use the cheapest gas you can find to go drag racing". I promise I won't make that mistake again. But, in the mean time I'm getting my car ready for this upcoming season and I want to start with fresh spark plugs.
My question is: Would you go to a colder plug for the start of this year. And, what kind of plug do you suggest, knowing the plugs I have seem just fine for my everyday driving and trips. 
BTW: I've checked the bible (Great FE Intake Comparison) and also checked online and can't find any reliable information on what I need to know.
Thanks guys.

[jayb]

"The Bible" LOL!  I don't know about that... 

I like to run Autolite plugs.  If you are running a stock ignition system use the 3924 plugs; this is a normal street heat range.  If you are running an MSD or some other high power ignition, I'd go a little colder, probably a 3923.  I use the Autolite Racing AR-3923 plugs in nearly all of my builds.

[fastback 427]

After one night of testing I run the autolites too. We hooked up several ignitions from stock points to msd 7al to our distributor machine and many different plugs to watch spark and the cut back electrode on the autolite was the winner. We don't have a pressure chamber to simulate a running engine like msd does, but it was the best we could do. Also for those running the big plug we run the autolite ar32 and ar33.

[mike7570]

Champions are junk, IMO. If it was acting up (your thinking it was fuel) it was probably the champion plugs.

[cammerfe]

Back when we were running the T-Bolt, Champion gave us all the plugs we wanted---by the case. And that was good because they lasted one run. Then we pulled them out and put them in the trash barrel. I still have marks on my arms, although not at all obvious after all this time, from doing the changes in the confines of the hot T-Bolt engine compartment.

Autolite also gave us plugs but they demanded that we give back the shells with the porcelain busted out in order to get a new case. But Autolite plugs would last for a full day of runs with no necessity for a change.

KS

[plovett]

I agree with all of the above about the Autolites.  I've used 3924's, 3923's, and 3922's.  I always come back to the 3924's.  They just work really well.  I run 10.5:1 compression on 92 octane and the 3924's are my choice.  I run a MSD 6AL and a Blaster 2 coil so maybe 3923's would be fine, but I personally like the 3924's. 

I've also experimented with larger plug gaps and rounded off electrodes.  I believe the as delivered electrodes work best and I like fairly small plug gaps.  0.035" is fine and I wouldn't go bigger than .040" for most applications. 

JMO,

paulie

[JimNolan]

Just what I wanted to know. Thanks Guys. Jim
Just ordered the AR3924's from Summit. I don't know what the AR does, but I want it.

[Bad Byrd]

Maybe I am nuts but I have tried Autolite plugs in several different cars, From the wifes 32 with a 383 stroker to a 347 Stroked SBF and I have yet to have an Autolite stay lit or run as well as a NGK plug. I can pull the NGK plugs out of Stroker SBC and throw in an  Autolite same heat range and same gap and it wont run nearly as smooth at idle.

Now it very well could be the combustion chamber of the FE motor, because almost everyone here swears by the Autolites...................but I will continue to run the NGK's until my FE tells me differently!

[My427stang]

I have found no significant difference between any brand plug on a motor that is running well.  That being said, I like the Autolites and the Champions, but the Champions seem to have a little longer electrode which I shy away from on a motor that is being run hard.

I run 3924s in aluminum headed FEs because you can buy them anywhere, although with modern ignitions I haven't had to.  Haven't tried the NGKs, but they were a very good plug for 2 strokes back in the day and could take a beating, even when mixtures were off, etc.

[Bad Byrd]

Ross

I have a friend that owns a shop here locally who has built the motors and tuned my last 3 projects. The wifes injected 383, The 850 HP lightning mod motor and my Turbo 347 car. And he is and was of the same belief as you. Until about 6 months ago when I lost the wide band on the roadster and I was fouling plugs like crazy.

He came over and we changed out the wide band and while there we used Autolites as disposable plugs to set the tune, He brought them. The car was all tuned up and running good and everything checked out fine. I pulled the autolites and threw in a new set of NGK's and even he noticed the difference.

He shrugged his shoulders and said................I do not know and have never seen a real difference between plugs accept for longevity. I have noticed it before on the turbo 347 car as well. Did I gain any more power....................never even checked, and till this day I cant explain it, I just know that the NGK plugs in those two application had a difference at idle and seem to stay lit for a long time.

[Barry_R]

I've run Champion race plugs in every EMC combo I've had for eight years.
So far I have yet to experience a problem with plugs.
I've also run the same plug in all the race style engines we've built - no issues.

For street oriented builds we run the 3924 Autolites.