S/C Spark Plug Gap

[Don Pfau]

Often my car experiences ignition break up over 5,500 rpm's. It shifts there now but I what to change the valve springs and have it retuned to rev higher. Which brings me back to the ignition. It has Scremin Demon coil packs on it and live wires. It has Autolite XP 104 Exteme duty plugs gaped at .050 I know the stock gap on the Mark is .054 and it was the same on the 03 S/C Cobra. But I was thinking the gap should be lower with the Marks ignition and the added supercharger ??

 

[lobird91]

What boost level are you running? Normally I run about .035 on boosted applications and also usually at least one heat range colder than stock something like a 103.

As a side note: I am not sure how the finewire XPs react with boost either as I have always ran standard autolites.

-Alan

 

[Right on the Mark]

Put in copper plugs and gap at .035.

 

[Don Pfau]

It's 6-7 lbs of boost. The plugs alway look good and they look like the right heat range. I once was told by a experienced builder to get rid of the Screamin Demon Coils and go back to the stock Ford ones ??? I couldn't remember for sure but I was thinking he said gap the plugs at .038

 

[Right on the Mark]

Stock coils are good. Like mentioned you should be 1 range colder then stock. Supercharged rule of thumb no crazy plugs and tighten gap.(spark blow out). You don't want stuff knocking off plugs or melting. Copper plugs best.

 

[Don Pfau]

I also learned Sunday that I could gain 2 to 3 tenths with a better torque converter so between the two I could be in the 11's

 

[philly0420]

From my experience the problem is with the Livewires, the SD coil packs worked fine. I switched back to motorcraft wires and threw those huge red wires in the trash.