coolrcdad, I have seen people use 2400's for stock 1/12th scale racing but they were very smooth drivers. With the amount of hp and the current the motors draw it is pretty close to dumping.
I would check with the person who you bought your batteries from. See what charging and discharging method that they used. Try to duplicate it as close as possible. Sometimes batteries don't like changes. Also, double check the battery forum on here and see what has been said on there.