Spark Plug Choice for Aftermarket Heads

[The Dan]

What plugs are you guys with alum. heads using? I'm currently running the original style BF-42 plugs, but don't know if I might get more benefits with a platinum plug install? My set up is in the sig.

 

[64.5 GearJammer]

I run Autolite 3924's in my Trick Flows

 

[66P51GT]

From the AFR site:
Spark Plug Starting Range Autolite 3924

 

[Great68]

Currently I have Autolite 3924's in mine, I used to have what I think was the Accel Equivalent.

 

[Hink]

Hi, The Dan . One important thing I have found out about plugs lately is, when going from iron cylinder heads to aluminum ones. The length of the threaded part of the plug needs to be a fair amount longer ! Or you're plug won't correctly stick into the combustion chamber, this in effect retards your timing, not a good thing. This may lead you to overtiming the ignition, in an attempt to get the engine to run good . Hope this is relevant.
Sincerely ,
Hink

 

[thehueypilot]

I run NGK 7942 (R5672A-10) in my AFR 225's. (which is equivalent to Autolite 3922 which is one step colder than the 3924 mentioned above.)

 

[2bav8]

Very happy with my Auto-lite 3923s with my AFR heads.

 

[HookandLadder]

Accel 761's, but that is with a bit of nitrous.