Not sure what the volt part of your analyzer is or how it is integrated with the tach/dwell part so I'll pass on that.
Even cars with breaker point ignition have a 6v ignition system even if they are 12v everywhere else. Sometimes the voltage is reduced by a separate ballast resistor, sometimes by an internal resistor built into the coil.
Since your tach/dwell connects to the primary wire between the coil and the distributor, it is really a 6v instrument. Only issue is whether to connect the red wire to the ground or to the points connection. If your car is positive ground like Mopar was from the factory, then the leads will be the opposite as what the instructions show.
I bought a relatively generic brand new tach/dwell meter a few years ago from my local auto supply which works fine on my '33. Only issue was it had to be ordered as they don't have a large demand for those any more. The did have all sorts of things for reading diagnostic codes from computers in stock, but not an old fashioned tach/dwell meter.