1/2 - bluff at big 4-way orphan pot?

SB squeezer is a spewtard, running 23/18/2.6, 3 betting 12%. BB is a big fish, running 48/12/2.8. CO is an aggro reg that seems spewy and bad and has seen me 5bet shove ATs pre, so might think I'm the same, he's running 25/20/3.3.

Bluff here? How much?

Full Tilt No-Limit Hold'em, $2.00 BB (6 handed) - Full-Tilt Converter Tool from FlopTurnRiver.com

saw flop

SB ($200)
BB ($196.85)
Hero (UTG) ($216.05)
MP ($227.70)
CO ($200)
Button ($319.35)

Preflop: Hero is UTG with 9, 10
Hero bets $7, 1 fold, CO calls $7, 1 fold, SB raises to $29, BB calls $27, Hero calls $22, CO calls $22

Flop: ($116) 3, 2, 6 (4 players)
SB checks, BB checks, Hero checks, CO checks

Turn: ($116) 2 (4 players)
SB checks, BB checks, Hero checks, CO checks

River: ($116) 5 (4 players)
SB checks, BB checks, Hero... ($171 eff. behind)

Hard to take it away without another barrel behind. Love $70 on the turn and shove into the loose player if he peels.

You have too much showdown value, you have like the 5th nuts here lol.

I wouldn't bluff this river. People check a lot of hands on the river again, when they think no worse is going to call but someone else might bluff.

I agree with Fnord that turn would probably be the place to start the bluff if we wanted to run one. We were PFR from UTG, I might even bluff the flop after 3bettor checks and another check.

If I'd want to bluff this river I think shoving could be best repping that the river hit you big time. It's probably not good though.