Voltage Regulator - electronic ignition

Your original charging system had 36 or 42 amps maximum. That was plenty when the car was new. Over time the resistance in the wire and connectors changes, thus the classic symptoms, headlights dim at idle, etc..
To upgrade to a 60 amp altenater will throw higher current and cause more heat which changes the resistance. So the connections will get better or worse.
I dont know what coil is used with the petronics ignition. The stock coil requires only 7 volts in run so even a weak charging system will cover it.
If you intend to add other electronics like sterio, whatever, you should upgrade the charging system for those.