Sounds right.. I have 728 grams as the nominal weight for those rods. That is indeed the normal spread of factory weights; I weighed a set with that much spread in rod weights.
You will probably have a bit better overall balance by putting the lighter rod with the heaviest on one journal, match the 2nd lightest with then 2nd heaviest on another journal, etc.
Were the rod ends resized after the ARP bolts were put in?
