75/150 River bluff #2

[ALL1N]

I'm pretty certain he's calling the turn with J5 and any gutshot + overcard, because this is effectively 10 outs to the hand I'm representing (threes). There are heaps of these combinations.

Now his river bet as you say is either an ace or a bluff. The pot has a bit of size by this point, and I don't mind spending 2 bets to take a shot at it. 7:2 is pretty decent.