This is how i see it and i am by no means right. You have 3 K's and 4 7's to make the best hand imo. granted a k loses you a few bets on the river if he has a monster, but if he has 77-99 then your outs are all messed up, vs 99 you have 3 outs and vs 77 you have 3. The way you played it i dont see you getting a free river enough even when he has QJ, but if he does your getting nothing more out of him.