Villain is 37.1/20.0/2.67 with a WTSD% of 13% over 70 hands.
He has been raising a ton recently and just bullying everybody around.
I figured there was a good chance he had a marginal hand when he check-raised me, and floated around with a gut shot. I decided to rep the king or some decent made hand on the river trying to get value from a weaker hand on the river. Good bet or spew?

Party Poker No-Limit Hold'em, $ BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

SB ($588.25)
BB ($597.68)
UTG ($697.14)
UTG+1 ($470.80)
MP1 ($594)
MP2 ($183)
MP3 ($1270.75)
Hero ($681.30)
Button ($578.65)

Preflop: Hero is CO with J, 8. SB posts a blind of $3.
5 folds, Hero raises to $18, 1 fold, SB (poster) calls $15, 1 fold.

Flop: ($42) 3, Q, T (2 players)
SB checks, Hero bets $30, SB raises to $75, Hero calls $45.

Turn: ($192) 7 (2 players)
SB checks, Hero checks.

River: ($192) K (2 players)
SB checks, Hero bets $150???