The coil may be marked as being for 24 or 12 volts....
The alternator...if it has a part number on it, see if you can get a parts house to cross it or maybe have a rebuild shop take a look at it to see if they can tell....there are gm type alternators that come in 12 and 24 volt...I have one laying around...
The stock fuel gauge only works with the stock military sending unit and needs 24 volts...if the fuel gauge hasnt been changed, could be a clue.
The bulbs in the light housings...if they have these numbers on the bulbs, then they are 24 volt:
1683, 1 used, large egg shaped glass part
1251, 2 used, smaller and round glass part
The 12 volt equivalents are:
1156 for the egg shaped
67 or a 97, both work for the round type
Lord send your Holy Ghost into our hearts and make the desire of our hearts Your Will.
Pro-choice, that's a LIE, babies don't choose to die!!