All spark plugs may look the same to the untrained eye. Unfortunately, nothing could be further from the truth. For starters, spark plugs come in many types that are mainly differentiated by the ...

Harley-Davidson’s Milwaukee-Eight engine carries four spark plugs across just two cylinders, a setup that strikes many riders ...

If you consider your spark plugs little more than disposable engine parts to be replaced for every event or two, you're missing out on a valuable engine-tuning tool. Not only can the correct plug ...

Oh, your Gen-III Hemi has two spark plugs per cylinder? Cool, cool, but let's up the ante, shall we? Oh, yes, three spark plugs per cylinder, now we're talking! Three-plug engines are to two-plug ...

When building a custom engine combination, it becomes a challenge to choose the right spark plugs, since there are often no factory reference points from which to start. And this is much more than ...