Yes of course, like I said 1000 watts would be better, it's just that most people would probably do 600 in that space. 1K watts will get real hot, and it will heat up that space real quick. You will need to spend a bunch more money on ventilation than if you went with 600. Of course 1K will cost much more in electricity. Also don't forget that besides the initial added cost of the bigger ballast, bulbs last a year or less, and the bigger they are the more they cost.

If you want big dense buds then grow a variety that produces those, and use a hydroponic grow method with the proper nutrients.