Im to am 26, 6'3 and 170lbs but after 8 weeks of a similier diet I'd actually lost weight. Im hitting 4900+ kcals a day now and im putting on a lb a week so far. So in answer I'd say it's more a case of a trial and error.
You need to make sure your eating every 2-3 hours and don't shy away from the good fats.
What's a typical days diet???