HI:
To add further to this last posting, in the refereed to site you will find:"Solid State Circuits To Replace Smiths Voltage Stabilizers".
The methodology used in the original 10v regulator(by-metal & contacts)has corrosion issues with the contacts.
I built one of the revised regulators with a chip(and a bit of soldering) a few years ago and it works fine.
Its easy to do and eliminates a potential poor reading of your dash gauges.