High volts

OK, so I cleaned the bulkhead connectors and checked voltages. Lemme know if any of this sounds not quite right...

At the switch side of the ignition switch, I'm reading 14.7V steady.
At the bulkhead connector, blue/white wire 14.7V,
at the ballast resistor, 14.5V.
Voltage at the excite wire at the alternator 14.5-14.6V.
Voltage at different points in the fuse box, 14.7-15.1V

I still show 40 ohms resistance between the (-) battery terminal and any chassis ground, but I only have factory style reproduction battery cables. I might put in a bonding strap between the engine block and the firewall, but I don't know how much good that will do...worth a shot though.