[jcassity]

Now, if.I'm not mistaken most car wiring is rated.for.apprx.12v... These old radios use voltages in the hundreds of volts. Are we sure.this would be safe?

yup,, your mistaken.  this is by wheelhouse.

Table 310.16 or 310.17 NEC , take your pick even at 75degC.

no company in thier right mind would ever manufacture a wire for a certain voltage.

The higher the voltage the smaller the wire can be.
walk ouside and take a look at the top tier of the telephone poles... thats the "high" line,, lucky if its even 1/0 alumninm.

the wire is 0-2000v standard issue.,, across the board for anything we do from your microwave, printer, soldering iron, lamp, lights in the house ect.

low voltage such as telecom facilities running -48v plants is where you gotta start compensating for no greater than 2v loss across the loop.

so in a nutshell, the wires in any car old or new offer a solution to color coding in a wide array of color combos.

Copper is copper,, ,, circular millimeters of copper has no care in the world what the voltage is.