i have a 1950 merc truck i want to run a 12 volt system and keep my 6 volts guages how do i do this

 

You will need a voltage reducer/regulator. Which you can get almost anywhere. When they switched over to 12V they didn't switch the gauges over they are still 6V. They put a reducer on the back of the instrument panel. They are easy to install they only have two connections, voltage in (from key) voltage out ( to guages), and a metal mounting braket that has to be grounded. I beleive there is a article on the tech section of this bullten board on switching over to 12V. Hope this helps.
Bob Wood