you ALWAYS connect battery chargers according to battery polarity. IE.. positive on bat charger to positive on battery.. negative on battery charger to negative on battery.
get the battery charged, get a new voltage regulator
install them, then jumper bat to arm on the reg for a second.. will see a spark.
remember positive battery POST to chassie... Negative battery POST to starter solenoid.
Ground is WHATEVER polarity is tied to the chassie.
then go for it.