From Another Place. I thought it might be useful.
Packard brand 7 mm plug wire or similar wire core - not carbontrack type . Copper or SS both work . Cheap brands have fewer strands . Seem OK tho as a high tension current flows OVER the surface of the conductor rather than through the wire , unlike a low voltage current which goes through the metal wire core .
Packard brand 7 mm plug wire or similar wire core - not carbon