2006max flopped boat against a tricky opp too tight on river?

[arod15]

Its very unlike me to play this tight. But i felt that this was one of those way ahead way behind hands. I thought there was no way he would call a big bet on the river and i didnt want to value bet and leave the door open from my oppenent. Although he played this one miserably, he was a tough match all night. We tried to stay away from each other. Comments welcome on all streets is check calling the river to weak tight?
Party Poker No-Limit Hold'em, $ BB (6 max, 6 handed) converter

CO ($91)
Button ($22.6)
Hero ($661.4)
BB ($138.11)
UTG ($644.84)
MP ($197)

Preflop: Hero is SB with 4, 3. Hero posts a blind of $1.
UTG calls $2, 1 fold, CO calls $2, Button calls $2, Hero (poster) completes, BB checks.

Flop: ($10) 3, 4, 3 (5 players)
Hero checks, BB bets $10, UTG calls $10, CO folds, Button folds, Hero raises to $35, BB folds, UTG calls $25.

Turn: ($90) 7 (2 players)
Hero bets $75, UTG calls $75.

River: ($240) K (2 players)
Hero checks, UTG checks.

Final Pot: $240

Results in white below:
Hero has 4s 3c (full house, threes full of fours).
UTG has 7s 5c (two pair, sevens and threes).
Outcome: Hero wins $240.