To give you some perspective, I can hold a weight of 245lbs at 4500 calories a day at 6 ft 2 and I'm naturally a skinny guy.
If you count 4500 calories accurately, it's probably 50% more food than you currently eat given you weigh 165.
You'll gain fat quickly and that's of no benefit. To gain quality mass, you will have to accept a certain degree of fat gain, it just comes with gaining weight in general, but don't do overkill because it's not doing you any good and is making you less healthy.
Whatever amount of food you eat right now, just increase it by 700 to 800 calories daily, much of it coming from protein and quality carbs.
I agree with this. I originally thought about saying something about your 6k figure, but most people underestimate their calories since they dont track anything.4k is more than plenty for your weight. I weigh 20 lbs more than you, and 3500 is my normal caloric range for gaining, and it works well.
500-1000 over maintenance per day is what you should do to limit fat gain