Spark Plug Wires & Accessories

How Do You Choose Spark Plug Wires?

Choose spark plug wires by matching diameter, core type, and fit to your engine and ignition. Diameter is the wire's overall thickness, and 8mm spark plug wires are a common performance size. Thicker options, like FAST FireWire 8.5mm sets or Taylor ThunderVolt 8.2mm wires, put more jacket between the core and nearby engine parts.

Core type affects resistance and how well the wire controls electrical noise. Check your ignition maker's recommendation, especially if you run EFI or an aftermarket ignition box.

Fit comes down to custom-fit or universal. Custom-fit sets are made for specific applications, such as FAST sets for GM LS trucks and Ford Windsor engines. A custom spark plug wire kit, like Taylor's 6- and 8-cylinder kits in black or red, lets you set your own wire lengths.

Before you order, confirm the boot style and terminal type your spark plugs need. For a deeper primer, read our Performance Ignition Basics guide.

Why Use Spark Plug Wire Looms, Separators & Dividers?

Spark plug wire looms, separators, and dividers keep wires spaced apart, secured, and away from heat and moving parts. Wires that run side by side for long stretches can induce voltage in each other, a problem called crossfire or induction. That can cause misfires, especially between cylinders that fire one after another.

Here's what each piece does:

• Spark plug wire looms hold several wires in a neat, spaced bundle along valve covers or brackets.
• Spark plug wire separators clip between wires to keep a steady gap along the run.
• Spark plug wire dividers split a bundle into individual channels so wires don't touch.

For a universal option, the Billet Specialties universal spark plug wire loom set adds a finished look to your engine bay. Keep wires from crossing near the cap, and secure them away from headers. If your cap or rotor is worn, replace it with parts from our distributors and components selection.

When Do You Need Spark Plug Wire Boots & Heat Sleeves?

You need spark plug wire boots and heat protection whenever wires pass near headers, exhaust manifolds, or turbo plumbing. Boots cover the terminals at the plug and at the coil or distributor end, sealing out moisture and dirt. Damaged boots can let spark energy leak to ground, which shows up as a misfire.

Plan boot and sleeve protection around these common hot spots on street and race engines:

• Plug ends next to header tubes, where boots sit close to exhaust heat.
• Wire runs along exhaust manifolds or crossover pipes.
• Wires routed near turbochargers or other high-heat parts.

A spark plug wire heat sleeve slides over the boot or wire to add a layer of insulation. Check the sleeve's inside diameter against your boot size before you buy. If you're upgrading more of your system, browse all ignition parts in one place.

What Are Coil-Near-Plug Wires on LS & LT Engines?

Coil-near-plug wires are short leads that connect each individual coil to its spark plug on GM LS and LT engines. Each cylinder gets its own coil, so the wire only spans a short gap. These wires sit close to the exhaust, which makes heat protection a priority.

Over time, heat can harden the boots and jacket. The misfires that follow are easy to mistake for a coil problem, so check each lead whenever you pull the coils.

Granatelli coil-near-plug connector kits for GM LS and LT engines use 0-ohm wire with high-temp silicone jacketing and fire sleeve. Granatelli also offers Performance Series wires with an 8mm jacket and fiberglass-reinforced braid.

If you're swapping an LS or LT into another chassis or relocating the coils, measure the wire length you need before you order. If your coils are worn or you're adding power, compare replacement ignition coils at the same time.

Which Spark Plug Wire Brands Does JEGS Carry?

JEGS carries spark plug wires from performance and OE-replacement brands, so you can shop by fitment, size, or style. Some brands focus on custom-fit sets, while others cover OE-style replacements or accessories. Here's where each brand fits:

• MSD spark plug wires for performance ignition builds.
• Taylor ThunderVolt 8.2mm sets and custom kits in black or red.
• FAST FireWire custom-fit 8mm and 8.5mm sets.
• Granatelli coil-near-plug kits for GM LS and LT engines.
• NGK Spark Plugs OE-replacement wire sets for stock-style repairs.
• Billet Specialties universal loom sets for clean wire routing.
• Scott Performance Wire spark plug wires, featured across this category.

If you're unsure which set fits, start with your engine family and ignition type. Then narrow your choices by diameter, color, and boot style. Shop Spark Plug Wires & Accessories by brand to compare sets for your engine.