This custom fit extreme heat ceramic boot spark plug wire set fits small block Chevy engines with HEI 1975-1986 wires under valve cover. ACCEL now offers the cure for burnt spark plug boots with Extreme 9000 ceramic wire kits. The 8mm Ferro-Spiral core wire now has ceramic boots on the spark plug end of the wires. Ceramic boots withstand up to 2,000 degrees. Great for running headers with close tolerance, an engine bay with little room, or an RV with boots that melt because of heat. Ultra high temperature double silicone construction wire rated at 600 degrees Fahrenheit peak. 500 ohms/ft Ferro-Spiral core developed for performance use. Excellent energy delivery to the spark plugs, while providing the highest level of RFI/EMI suppression. Stainless steel spark plug terminals for maximum spark energy to the plugs. Pre-made to factory lengths for a perfect fit.