While many will be quick to just purchase OE replacements straight from a dealership ... and water-tight seal, while the terminal design improves spark plug retention and assists installation ...

More specifically, how about those spark plug wires you're running ... Your exhaust will also dictate what plug terminal boots to use-90-degree or straight. More often than not, tight headers ...

Read a good spark ... plug isn't firing. It could be that the plug itself was fouled or shorted with deposits to start with, but it could also be a bad wire, distributor cap, plug terminal ...

The spark-plug wire also might have had a corroded end terminal or torn conductor. Should you repair the offending spark-plug wire? Assuming you keep your hands clear in the future and the car ...