how old is this 'hemi'? are you talking the original FirePower? wasn't Chryco 12V neg by the first actual hemi?
to change over, disconnect the battery cables and switch them .... if the ammeter reads backwards you'll know to switch the wires on it [but it shouldn't as it was from the neg ground system] - don't think the starter could run backwards [older GMC's w/ pos ground don't have a problem] .... should still run without changing the coil, but switching the connections there will make the points last longer .... should re-polarize the generator .... changing to an alternator takes some re-wiring anyway, depending on if it's internal or externally regulated
Bill
