RLP Universal Spark Plug Wire Set 8.5mm Red Silicone with 90° Boots — High-Temp, RFI-Suppressing Ignition Wires

RLP Universal Spark Plug Wire Set is an 8.5mm high-gloss red silicone ignition wire kit with 90° boots engineered to increase spark delivery and resist heat, moisture, and chemicals for street-driven vehicles.

This RLP wire set upgrades original-equipment ignition wiring for improved spark energy and durability in both universal and custom-fit applications. Built with a conductive carbon-black core for RFI suppression, EPDM inner insulation, and a tightly woven fiberglass braid covered by a 450°F-rated silicone jacket, the set is designed to meet or exceed SAE standards for ignition performance and longevity.

How does this wire set improve ignition performance?

The wires use a low-resistance (approximately 5000 ohms/ft) conductive core that lets more ignition energy reach the plug, producing a stronger, longer-lasting spark. Reduced electrical interference helps stable ignition timing and cleaner firing under load.

• Conductive carbon-black core for effective RFI suppression
• 5000 ohms/ft resistance balances energy delivery and interference control
• Stainless steel plug terminals for reliable conductivity and corrosion resistance

Will they withstand high under-hood temperatures and contaminants?

Yes — the wires are wrapped in a double-layer silicone jacket rated to 450°F, offering resistance to heat, oil, and road chemicals. The tightly woven fiberglass braid under the silicone adds mechanical strength and helps terminal retention under vibration.

• 8.5mm high-gloss silicone jacket resists heat and chemicals
• Fiberglass braid improves pull strength and abrasion resistance
• EPDM inner insulation provides high dielectric strength

Are these wires compatible with my vehicle and installation types?

The set is offered for universal and custom-fit installations across many early and late-model cars and trucks and is a direct replacement for part number 4041. They work with pre-HEI and post-HEI ignition systems, making them versatile for restoration or performance upgrades.

• Replaces part number 4041 for direct-fit or universal routing
• Compatible with pre-HEI and post-HEI ignition systems
• Available for universal/custom-fit applications to suit routing needs

What durability and warranty protections are included?

The combination of stainless steel terminals, fiberglass braid, and a high-temperature silicone jacket extends service life and resists environmental degradation. RLP backs the wire set with a two-year warranty for added peace of mind on street-driven vehicles.

• Stainless steel plug terminals resist corrosion and maintain conductivity
• High-strength construction designed for longer terminal retention
• 2-year limited warranty from RLP for manufacturing issues

Who is this for? The RLP Universal 8.5mm Spark Plug Wire Set is ideal for owners restoring older vehicles, upgrading ignition wiring on street-driven performance cars, or anyone needing a universal or custom-fit replacement for part 4041. Choose this kit if you want improved spark energy, better RFI control, and durable materials that tolerate extreme under-hood conditions without sacrificing appearance.