Charging problems

If the voltage regulator is doing its job, you will measure ~14.3 V from its case to the IGN (blue wire, right at Vreg), with engine idling (or slightly rev'ed). If original, yours is the old electro-mechanical type. The terminals are exposed, so easy to touch w/ multimeter leads. If true, your job is to insure minimal voltage drop from VR case to BAT- and from BAT+ to IGN (right at Vreg). Drops are common on the gnd side from rusty sheet-metal screws, and on the high-side from the path thru bulkhead connector (twice), key switch, and fuses. Those voltage drops cause over-charging (BAT- to BAT+).