Plug # and Plug Gap Info Needed

[Mike Z]

I have a Mopar 400 Stroked. I'm Getting the dual quad carb issues straitned out. Time for a fresh set of Campion Plugs. Low Compression Motor that has 14's in it. Should I run a 14 or a 12? With MSD Ignition What Should I gap em?
Thanks in Advance,
Mike Z.

 

[Stumper]

No expert here as I'm trying to sort out which to use in my motor right now myself, but I would think the cooler 12YCs might be better if you have a modified motor. How did the 14s run in it?
You may even want to drop down to a 9 or 10s - depending on what all you have done to the motor. Standard gap is 0.035" which is probably good. With a high voltage systems you might benefit from 0.040" gap - especially if you drop down in heat range.

 

[terzmo]

I found NGK's in My 340 gapped at .060 (msd system) and switched to champion 12Y's and gapped at 038 and starts/runs excellent. Understood Yours is a Big block but I ran champions in all My BB and gapped the same and they ran well also

 

[Cazbah362]

MIke - I am running a RB with CH25 dual quads at about 5,000 ft alt. I run it at about 36 advanced and with .060 gap with MSD system, runs great, no issues. When I had it at .035, I was fouling plugs

 

[67 coronet]

the more powerful your ignition sytem=the larger the gap.larger spark area=more fuel burned.35 gap is for std point ignition.it kind of becomes a trial and error deal to find the right gap for your car.heat range also has an impact.cooler plugs for motors with more performance potential.try some different stuff,plugs are relativley cheep.