Its not the wire, its heat...tranyduster,
Now before Ya'll go bashin on Me, ...
Go to a local Bone Yard, find a 6.0L GM,
Pull all the spring loaded boot heat shields, cut down the 'open end' & shorten
the release spring as needed, Done & Done...
Oh, one caveat,
just to really anger the purists LOL !!!
Put a liberal amount of D7AZ-19A331-A Motorcraft Silicone Dielectric into the plug boot
(spark plug end).