The Pros and Cons of switching from a 6-volt system to a 12-volt system.
A 12-volt system makes the tractor start easier and the alternators are able to keep a battery fully charged after just a short time running, on most tractors by switching to a 12-volt system you can also use a hotter ignition coil which helps to burn the gas we have today.
The downfall to switching to a 12 volt system is the tractor will now have an alternator which on many tractors is in full view, and some people frown on this look as it doesn't look like the original generator (some generators can be converted to 12 volt check with your local starter-generator shop for more info). The other problem is the starter is now spinning faster so the drive can prematurely wear the teeth on it and the flywheel ring gear.
Make sure you have all your facts in line before you start a conversion.
JR