Jay, Standard ignition wires are 7mm, Bosch and others. High tension wires using MSD ignition systems and others are sometimes 8mm wires. Unless your experiencing some kind of trouble, I wouldn't see how 7mm wires of high quality would give you any trouble. New wires are carbon suppressed for interference purpose and may offer some resistance. I don't know if you can even buy straight stranded copper wires any more. FCC may have something to say about it. John Hervey www.specialTauto.com << Has anyone has had any experience or success with any performance spark plug wires, spark plugs, or ignition components? The stock wires seem like they could be better. Jason Voorhees #2848 >>