Only if the points are open, if they are closed you should have 8.4v on the coil + and zero on the coil - (12v negative ground system).
Properly setup your 12v conversion should have bypassed the ballast (ignition) resistor providing full system voltage to the coil + in start, only.
Sounds like your starter solenoid is bad. You can run a temporary jumper, for testing purposes only, from the coil + to the battery + and see if it starts up properly, if so it's the solenoid or the wiring for the ignition start circuit. Make sure you are in neutral because you will not be able to turn the engine off until you pull the jumper.