Spark Plugs & Leads

Spark Plugs & Performance Ignition Leads

The spark plug is the final link in the ignition chain — the component that actually produces the electrical arc that ignites the fuel-air mixture. And the ignition lead delivers the high-voltage pulse from coil or distributor cap to the plug with minimum energy loss. Getting both right is fundamental ignition system maintenance that's easy to overlook but has a direct effect on performance, fuel economy, and long-term engine health.

With 428 products from ACCEL, MSD, NGK, and ProConnect, our spark plug and lead range covers both standard-specification replacement for maintenance purposes and performance-optimised components for modified applications where ignition system quality directly impacts power output.

Spark Plug Heat Range Selection

Spark plug heat range is one of the most frequently misunderstood aspects of ignition system specification. The heat range determines how quickly the plug dissipates heat from the firing tip — a cooler plug dissipates heat faster and is used in high-performance applications where the plug tip would otherwise reach temperatures that cause pre-ignition; a hotter plug retains more heat and is used in cold-running applications to prevent fouling. Factory heat range recommendations are appropriate for stock engines; modified engines with increased compression, forced induction, or aggressive timing often require a one or two step colder plug to prevent detonation from plug-induced pre-ignition.

Performance Ignition Lead Sets

A quality set of ignition leads does two things that cheap leads cannot: it delivers the full voltage produced by the coil to the spark plug without the resistance losses that sap spark energy, and it suppresses the electromagnetic interference that performance ignition systems generate and which can interfere with electronic systems throughout the vehicle. High-performance leads with quality spiral-wound suppressors and thick silicone insulation provide both benefits in a package that's resistant to the heat and chemical attack of the engine environment.

Lead routing and separation is also important — leads bundled tightly together can induce cross-firing at high voltage, particularly in high-energy ignition systems. Quality leads with appropriate separators that maintain correct routing contribute to consistent ignition performance across all cylinders at all RPM.

Complete Tune-Up Kits

Tune-up kits combine plugs, leads, cap, and rotor in a single matched set — ensuring all ignition wear items are replaced simultaneously with components selected for compatibility. For vehicles undergoing a full service or preparation for the season, a complete tune-up kit is the most straightforward approach to ensuring the ignition system is performing at its best.