Mike,
I run both my Carrier with 6 volts and the original generators. If well maintained they start, run, and charge as well as a 12 or 24 volt setup.
With the old car guys parts suppliers pumping out bulbs, voltage regulators, cutouts and batteries in all voltages, the 6 volt stuff is no more expensive to set up than something 'more modern'.
Once the coil on the distributor is fixed on the flatty, all is well.
Stewart
PS - for all the guys who might need one, our pal, Tommy Allen has a rebuilt Ford for sale. he told me that he wants $2K for it, and it has a few hours on it driving his big welder on the back of that truck of his. The 2 he has on the beast now run fine, so I suspect that tis one would be just the thing to slip into any CMPers Xmas stocking ...