Magnecor is probably right, and there's a much simpler, and possibly less expensive solution to the (virtually nonexistent) problem you're describing. In 50-something years of doing and teaching auto repair, I cannot recall seeing a single instance of rodent-chewed ignition wires on a vehicle in regular service, and ridiculously few examples on vehicles in long-term storage or even a junkyard.
If you insist on having metal-armored wires, use the ones designed for aircraft engines and modify the ends to work with automotive type spark plugs and distributor caps. Shielded wiring has been in use on aircraft engines since before WW II, and on many military road vehicles for about as long. The Viet Nam era M-151 Jeep I bought in 1971 had that type of ignition wires so the engine could be run submerged in water with a snorkel kit. There's nothing new under the sun!
Jerry
