ignition and charging system question

I was wandering if there was an easy way of telling if the ignition system and charging system have already been switched over to twelve volts? I havent really looked over the ignition system all that well but the altenator on my jeep looks like just a regular chevy altenator. When I first got it my first goal was to get it to turn over, after trying with two batteries run in parallel the starter wouldnt even turn the engine over (it sounded like the batteries were dead). I then tried running the batteries in series, it sounds like it is turning the engine over with the spark plugs out of it (turns over very fast). Is this normal? The wiring harnass was pretty much useless from dry rot and some dummy wire nutting all the connections together, I rewired the truck and of course was so anxious and in a hurry I didnt bother to look the way the 2 systems were already ran! I dont think that it would of been wired right to begin with because the batteries were already ran in parallel for the starting system when I got it. The way I ran the starting and ignition systems was that I ran the batteries and pulled 24 volts for the ignition system (two batteries in series) and then pulled 12 volts off of one of the batteries for all of my lights and accesories. My next question was, will the polarity of the batteries ever change over time? (the posative and negative in the middle become obsolete)

I know on mine (and I'm still learning) my dizzy cap does not have the screw on plug wires, civvy 12 volt, and a chevy altenator. My wiring is all hacked up also so I'm starting on replacing it with a harness out of a Grand Wagoneer. Not much help but hope it's some.

The stock 24 volt alternator is HUGE compared to the Chevy S10 alternator.

I couldn't or didn't find it in your post. Do you have the military distributor with shielded wires that have to be screwed in at both ends and real funny looking spark plags that have a threaded "Barrel" on the wire end or a regular civilian looking distributor with push in wires and regular spark plugs?

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

I still have all of the original ignition on the truck, all of the shielded wires and the goofy distributor. Is the coil located under the cap? I printed out the user's man. I think that is what remember out of it.

The military ignition has at its center the Ignitor....which is a single housing with the coil and distributor inside. The actual distributor cap is inside the ignitor housing, screwe up to the lid of the igntors housing.

You should be able to pull the coil out and find the voltage on the side along with some other info.

if it has a 12 volt alt, it may be converted over already but you need to check everything to be sure. if you run 24 volts thru a 12 volt circuit, you can fry alot of componant and vice versa. pics would help also as some of us can probably help identify a possible conversion.