Brian, have you read the 12V conversion tip in the "Tip Section" on Stovebolt?
The following comments are without knowing the year of truck and any mods/changes to electrical except you are going 12V with a new harness.

You only have one electrical gauge (gas). ..and one electrical meter (Ammeter). Oil and temp are mechanical.
The gas gauge gets a simple voltage reducer inline and the ammeter may or may not be suitable. probably OK. can also be bypassed/replaced/shunted/abandoned in favor of a voltmeter or idiot light.

Yes 100% should be in electrical section.


Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn