[LPete]

AutoLite makes Motorcraft spark plugs for Ford. Can't be all that bad What vehicle manufacturers use NGK for OE plugs?

Almost all Japanese cars use NGK or Nippon Denso.

 

[LPete]

Look at Permatex antiseize — it’s a mixture of copper, aluminum, and graphite.

But that doesn’t really matter, anyway. 10 or 15 kV doesn’t really care about a small amount of resistance. Take a plug out and hold it away from something metal. Crank the engine. The spark will easily jump both gaps — the one on the plug and the one from plug to ground. There’s nothing special about the ground side of a circuit that requires very low resistance.

 

[LPete]

The gap was about 1.8 x spec, if I recall correctly.

This isn’t very good for ignition secondary components like plug wires and coils. Modern coils will likely be capable of putting out enough voltage to fire plugs consistently with gaps this wide, but that high voltage is trying to find easier paths to ground, and that means it’s trying to go through the insulation on plug wires and coils. This can and will damage them.