Considering it is a 6V coil, 7.3V is more than acceptable. Welcome to the wonderful world of Chrysler ignitions.
Back in the 50's when everybody was changing over to 12V electrical systems from 6V, Chrysler decided to do things a little differently, compared to GM and Ford. F/GM (can't stand to type those words) took the easy way out and just switched everything to 12V, from heater motors, lights, etc., including ignitions. The Chrysler engineers (who ran the company instead of the bean counters) who did the ignition, did some cold start testing and decided to keep the old 6V coil and add a ballast resistor that could be switched in and out of the circuit. The testing showed that voltage to the coil could drop as low as 6V during starter motor engagement, which did not supply enough current to fire the plugs with a 12V coil and resulted in the same hard starting situation that doomed the 6V systems. By installing a resistor in series with the coil that could be bypassed during starter engagement, and in the circuit during normal operation, the coil would always see at least 6V. Best of all, it only cost a resistor and relay and was almost as cheap to do as a 12V coil. Hope this helps.
