My mistake not addressing accuracy. I was only talking about the proper voltages and damage to the tach itself.
Just to clarify, the voltages present with capacitive discharge systems are too high for factory tachometers to handle and will result in permanent damage. Conventional Mopar systems, points or electronic, will not damage the tach. It still may not read right as the wave forms are not what the tach expected. Dwell on points systems was usually much longer and adjustable. On electronic systems, while somewhat adjustable by adjusting reluctor gap, it is much shorter and presents a different duty cycle to the tach than it was expecting.
Craig