Ignition wires get warm
Hot wires are indication of a problem.
Were there any changes or upgrades in electrical anywhere at all?
Reason I asked is because most will add electronic ignition, isolated field charging system, etc.., that get their power through the ignition switch. When the factory added these things in 1970, not only did the ignition switch move to the steering column but the wires going to and from it got larger. Even those would melt down at their connection below the steering column if overloaded.
Some rallye panel owners believe they can throw a solid state gauge voltage regulator in on top of the original mechanical limiter too. That doesn't work and can lead to the problem you have.