So I have been looking online and am struggling to come up with a definitive answer for what parts are needed to convert a 6 volt system over to a 12 volt system. So far I have the arts that need to be changed: battery, generator to alternator, ignition coil, ballast resistor, and potentially positive ground to negative ground. Now I plan on changing out the plugs, wires, points and condenser, cap and rotor because the motor has been sitting for 15+ years. I am willing to put some money in it to get it running but don't want to buy parts only to find that I need to replace them because they won't handle 12 volts. Are there any parts that I am missing? I am not concerned about the lights because as the truck sits it is just an engine sitting in a chassis. The motor has the distributor set it the front of the block near the top on a 45 degree angle, which I have been told means it is an 8BA, the previous owner agreed. Also does anyone know the torque pattern for the 24 bolt heads, and the torque specifications? I will be removing them to un-stick the valves if needed. The motor turns over freely enough and the previous owner "bumped" it over to help move it. Thanks in advance for your help!

 

Starter relay also needs changed. Changing from positive to negative ground is no more than swapping the wires to the opposite side. Here is the info.

 

If you want reliability, basically every electrical component that isn't a wire, a manual switch, or a connector will need to be swapped out. 12V systems require only 1/2 the amperage of a 6V system to do the same work, so the 6V wiring and switches should work fine, but any relays, ignition parts, motors, light bulbs etc. may run on 12V for a little while, but will experience premature failure - some more spectacularly than others. The light sockets may or may not work with 12V bulbs simply due to configuration issues.

I have seen a couple of conversions that use a 12 volt alternator to charge two 6V batteries in series and then run the electrical systems on 6V by picking 6V off the batteries separately. However, if you aren't very careful in the the rewire, it's easy to screw that up and put 12V where 6V should be, since you essentially need 2 different isolated ground buses. It's really more trouble than it's worth.

Swapping from Positive ground to Negative ground isn't a big deal but realize you will probably need to swap out or rewire any motors and possibly swap or rewire the gauges as the current flow will be reversed.

 

Yea not worried about lights at all because when I add them to the truck they will all be ran as 12V. As the truck sits it is an engine and trans, so the only things I am worried about are the distributor parts, plugs, wires. Will these parts be able to be run on 12 volts. Also I have a friend that says all I need to do is run an ignition resistor and it'll be good to go. Here is the truck as it sits to give you an idea of what parts actually need to be swapped.

 

When it comes to the ignition parts, i.e. distributor, cap, spark plugs, plug wires, points, etc, almost nothing needs to be replaced. The main item that would need to be replaced is the ignition coil if you will be going from 6V positive ground to 12V negative ground. Your friend who recommended the resistor is correct and that is a simple option to employ. Dodge/Chrysler/Plymouth did the exact same thing for years. They used a resistor to reduce the voltage from 12V to 6-7V on their vehicles from the 50's all the way into the early 70's. In fact, the 40's Ford trucks used a resistor to reduce the voltage going to the ignition coil from 6V to about 3.8V. The resistor is under the dash bolted to the firewall just forward of the instrument panel. Of course, you have no body on your truck so it is not there. It would not work with 12V so you would need one that reduces 12V to about 6-7V and change the ignition coil. Now you can also purchase a coil with an internal resistor already inside it. Some like them and some don't. The coil you purchase will most likely be marked with a + and a - on the terminal posts. For 12V negative ground systems, the wire from the distributor will go to the - terminal post and the wire to provide power will go on the + terminal post. The starter doesn't care whether it gets 6V or 12V or whether it is positive or negative ground. It will work the same on either voltage or ground but you need to be careful not to crank on the starter too long when you use 12V. As mentioned above, the starter solenoid will need to be upgraded to one that works with 12V negative ground. Good luck!

 

The starter windings are meant for 6vdc and some ungodly amount of amperage. 35 comes to mind. 12v is half the amperage, so the starter won't care how long it's cranked. All dependent on age and former abuse of course. You can leave the starter alone at 6v until it fails and then change it to 12v if you like.