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FE Power Forums => FE Technical Forum => Topic started by: happystang on March 24, 2019, 11:26:39 PM

Title: Spark plugs for 428
Post by: happystang on March 24, 2019, 11:26:39 PM

What is everyone using? I've got Edelbrock heads with Autolite 3924 plugs. I'm tempted to use an NGK plug a heat range colder. (Gap recommendations?)

Specs:

428 .030 over
Edelbrock heads (10.5:1 compression)
Lunati Voodoo hydraulic roller cam (.559/.559 lift 211/219 duration @ .50 112 LSA)
Edelbrock RPM intake
Holley 750 DP
Pertronix III distributor and coil

Engine is in a '68 fastback with a 4 speed.

Title: Re: Spark plugs for 428
Post by: plovett on March 24, 2019, 11:32:16 PM

You've already got the right plugs.   I've tried colder on my 10.5:1 428.  The 3924's work better and I don't seem to have any detonation problems.

I like smaller gaps, like 0.035".  I've experimented with wider gaps and never found any improvement, but did find that it didn't seem to run as good.

JMO,

paulie

Title: Re: Spark plugs for 428
Post by: plovett on March 25, 2019, 12:02:21 AM

I've also tried some "tricks" like filing the corners off the plugs, because I was so afraid of detonation.   It didn't help and made the engine run poorly.  I have tried Autolite 3923's and 3922's.  I don't have 1/4 mile times or some other analytical data, but just seat of the pants impressions.

With Edelbrock heads, the Autolite 3924's with a 0.035" gap will work with 99% of combinations.

JMO,

paulie

Title: Re: Spark plugs for 428
Post by: 427LX on March 25, 2019, 10:11:26 PM

I use same plug in my aluminum headed 427 Windsor and went with the Autolite XP3924 with iridium tip.
Should last a bit longer and allow better spark.

Title: Re: Spark plugs for 428
Post by: fryedaddy on March 25, 2019, 10:20:19 PM

are the E3 plugs any good.i seem to see alot of people using them on tv shows and videos.