Giving these Champion racing plugs a try

[bigmanjbmopar]

So far so good, went with ones a little on the colder side. noticed that the anode didn't go all the way over the electrode it seemed to run fine gaped them at 35 they were all pretty tight out of the box so not sure what the real gap should be?

 

[RustyRatRod]

What kinda ignition are you runnin? That dictates the gap.

 

[Meep-Meep]

Also compression ratio must be taken into account. Probably not the case here, but very high ratios tend to blow the spark out so you want a tighter gap to ensure you get a spark. Low compression can benefit from a high energy ignition and a wide gap. I'd run the hottest plug you can without burning down the motor, and generally the HP stock heat range works well for a hot street motor.

 

[bigmanjbmopar]

MSD 6AL with Mech advance distrib compression is 9:6:1 I had my diamond pistons dished -24cc so the compression would be below 10 to help with today's gas.


http://www.jegs.com/PDFs/ChampionRacePlugs.pdf

I am trying to C59YC it is on the colder side, had already experimented with NGK FR4 If these don't work out meaning oil foul due to being colder I will either try a hotter one like the C63YC or FR5 series I guess the V groove is supposed to be Superior according to Kenny Bell

 

[RustyRatRod]

I would try .035-.045 and see how that works.

 

[Meep-Meep]

If you do a lot of street driving you really want a vacuum advance. I won't run a street car without one.

Unless you have a PG&E substation under the hood I also think a gap in the .035" - .045" will be about right. I'm running .035" in my 10:1 440 and using an orange box. Hasn't missed a beat.