X4XZ HEI Spark Plug Wire Set for Chevy V8 — 10.5mm 9-Piece Blue Silicone, High-Temp

High-temperature 10.5mm HEI spark plug wire set by X4XZ — a 9-piece replacement kit engineered for Chevy small- and big-block V8 engines including 350 and 454 models.

This complete wire set is built to restore reliable spark delivery and tidy engine bay routing on classic Chevy SBC and BBC V8s. The kit includes a mix of black 90° distributor boots and straight plug-cap boots, heavy-duty silicone sheathing, and a pure silicone insulator designed to resist heat and voltage. It’s a direct-swap option for many factory HEI setups and an economical way to renew ignition performance and appearance.

Which Chevy engines and years will this X4XZ 10.5mm set fit?

The set covers a wide range of Chevrolet small- and big-block V8s, including common SBC 302–400 and BBC 348–632 families. Fitment extends across many model years and applications from classic Corvettes to trucks and vans. Always confirm vehicle compatibility before ordering using your vehicle’s year, engine and distributor type.

• Compatible engines: SBC 302/305/307/327/350/400; BBC 348/366/396/402/409/427/454/496/502/572/632
• Designed for HEI distributor systems and HEI-style coil caps
• Check vehicle fitment lists and pictures for model-year specifics

How are the wires constructed to handle hot engine conditions?

X4XZ uses a pure silicone insulator with a heavy-duty external silicone sheath to tolerate high under-hood temperatures and sustained voltage. The materials minimize cracking, arcing and electrical leakage, helping maintain consistent spark paths under load. Boots are high-temp rated to preserve sealing and connection integrity.

• 10.5mm thick silicone insulator for heat and voltage resistance
• Heavy-duty outer silicone sheath to prevent deterioration
• High-temperature black boots for long-term reliability

What do the included boots and ends look like, and why matter?

The kit contains both 90° distributor-style boots and straight spark-plug style boots to match HEI layouts and common plug angles. The 90° distributor boots are intended for the coil/distributor cap interface while straight boots connect at the plug ends for a clean fit. Proper boot angles ensure secure connections and help avoid misrouted wires or stress on terminals.

• Black 90° boots for HEI distributor/cap connections
• Straight black boots for spark plug ends and coil cap HEI designs
• Pre-formed lengths to help accurate routing and minimize crossfire risks

What’s included and what support does X4XZ provide?

The package ships nine blue-insulated spark plug wires arranged to replace a full V8 HEI wiring set. X4XZ offers customer service and a one-year product service period for installation or quality questions. Keep your order details and vehicle information handy when contacting support for the fastest help.

• 9-piece spark plug wire set (blue wires with black boots)
• One-year product service and 24-hour customer support
• Installation assistance available from X4XZ customer service

Who is this for: Enthusiasts and mechanics restoring or maintaining classic Chevrolet V8s who need an affordable, heat-resistant HEI wire set that matches common SBC and BBC applications. The X4XZ 10.5mm kit is suited to owners replacing aged, cracked, or underperforming wires in Corvettes, Camaros, Chevelles, trucks, vans and other period Chevy vehicles that use HEI-style ignition systems.