Dig deep? What? You didn't ask about RUNNING voltage. You didn't specify running voltage. Here's your quote: "Is the oem voltage at the coil 6v?" If we start assuming what you meant, we might get it wrong. That's why we need all the info we can get. We're still assuming a lot since we still don't know what ignition you have....so I'm assuming it's factory Chrysler. Is that a safe assumption? Remember, while you know your car, we do not.
The RUNNING voltage depends on which resistor you have. Usually it's around 8v running. Yes you can run hotter voltage by running a different ignition that fires on 12V, such as the GM HEI conversion. The Mopar style boxes must use a resistor or they will burn out.