• Custom Sets are factory terminated on both ends and made to length to fit your specific engine. Wires are matched to factory specs using the OEM factory looms, dividers and wire sizes. Sets come with straight, 90 degree or 135 degree style spark plug boots, or a combination of styles, depending on your engine. If you have changed your engine at all, aftermarket valve covers, headers, etc., we recommend you select from our Universal Spark Plug Wire Sets. The Universal Set allows you to fit the spark plug for ideal header/block clearance with either style boots. • Universal Sets are factory terminated on the spark plug end only and made with plenty of length so you can tailor the wire to your exact length. You must cut, crimp and terminate the distributor cap end to complete the installation. To cut and terminate the distributor cap end requires a heavy-duty wire crimping tool for a factory style crimp. (Available from local NAPA stores and others.) Do not use needle-nose pliers to crimp wires, as your wires will fail. You may select sets with factory terminated spark plug boots with either all straight, all 90 degree or all 135 degree style spark plug boots. If your current engine set-up has a combination of spark plug boot styles, the universal sets will not fit your engine.