5/10 deepish River Shove

[DenGreek]

Full Ring, Live, 5/10 NL. Villain just sat down about half hour ago. He has around 1800, I cover. No real reads excpet he knows some of the better players at the table, however he is not a regular, but probably a good thinking player.

Villain makes it 60 from MP, CO calls, I call with 54h on the button.

Flop 6 7 7

Villain leads for about 120, CO folds, I call

Turn 5

Villain bets about 250, I call

I figure he has over pair at this point, and my plan is to rep 98 on almost any river, after flatcalling the turn.

River 4

Pot about $930ish, Villain bets around 400. This really confused me. I don't think he would value bet with a set of 7s or overpair, so I think he has 88 or maybe AA/KK/QQ. I go with my plan and shove for 1700, making it around 1300 more for villain to call.

Thoughts on all streets? Is this a standard shove vs thinking opponents?