No spark

I would pull the wire from the coil to the dist. place it close to a ground (motor but dont touch the motor) and turn the motor over. If it sparks you have fire to the coil and should be good. If you have spark then pull a plug wire and do the same. When this happened to me I was getting fire to the coil and not the plugs. My points had closed.
If the PO bypassed the 6 volt system just means the battery dont go to the lights. If your alt is 12 volts you should have the power need if I am correct there.
But this is just my .02 worth. Hope it helps.