also have seen some of the 7mm Delco hi temp orange wire with gray color ends (plug side)
I don't know if this wire was all made by one wire company or one company that would supply the wire co with materials but the 7mm hi temp wire
of the late 60s early 70s I see a lot is the burnt orange color, steel core wire.
It was used by Delco, Motorcraft, AutoLite, Ramcharger, Mallory, and others.