Radio frequency noise suppression ignition "wire" has been in use since the early 1960's. It's not wire at all, but a piece of string infused with graphite and other conductive material. It can have a resistance of up to 1,000 ohms per inch. It's there to suppress the magnetic signal generated by current passing through the ignition leads that causes interference with radio and TV signals. A yellow spark is normal. The "hot blue spark" that people still look for is as obsolete as a hand crank for starting an engine, or a carbide generator to power acetylene headlights. Using wire-core ignition leads will cause rapid erosion of the contacts inside a distributor cap due to the high current involved, however.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!