$50 SNG on the button with Ac6c

[Mikey]

i'm playing in a live $50 SNG.

We started with $1500 in chips, 6 players, the blinds now are 40-80.

I'm on the button with Ac6c and pretty much with $1400 in chips, my opponent is to my right and he is sitting on around $2000.

The action is folded around to my opponent who limps.

A little info.
He had previously open limped with QQ in the cutoff, I had the button and folded. The SB completed with 98o and the BB checked.

The flop came 8 6 2, the SB bet and the cutoff called.
Turn was a T, SB bet and cutoff called.
River x. Check check.

We were all a little confused at his play, but he's not sophisticated and he used to play a lot of basement poker but hasn't kept up with poker. Its a few days before X-mas and he's looking to have a good time as well as win a little money.

So onto my hand, he limps in the cutoff and i limp with Ac6c.

the SB folds and the BB checks.

The flop is As Td 8d.

BB checks, villan checks I bet. $200 into a $280 pot.
BB folds, villan calls.

Turn is a 4c.

he checks $680 pot.

I bet $350 he calls again.

River is a 2c.

He checks. The pot is $1380.

I think about turning my hand up but figure maybe there is a little room here for a value bet, afterall he may call me with a T in his hand, and also if he does fold because he has missed his draw my opponents don't get to see what he limped in with nor do they get to see what I have bet with this whole time. 2 opponents in the game are very observant .

I figure a $400 bet looks about correct. Just enough to squeeze a little more value out of my hand.

What do you think?