Flop quads, then get raised!

[J-Bo]

6-handed 200 NL. I have 200, opponent covers.

Opponent is a solid winning regular. He's fairly tight, though I've seen him raise c-bets with bare, non-nut flush draws.

I think he has exactly 44, or 10-10+. How to extract?

I'm UTG with 8 [img]/images/graemlins/club.gif[/img]8 [img]/images/graemlins/spade.gif[/img]

<font color="red"> Hero raises for 8</font>, CO calls, everyone else folds.

Flop 8 [img]/images/graemlins/diamond.gif[/img] 4 [img]/images/graemlins/spade.gif[/img] 8 [img]/images/graemlins/heart.gif[/img] (pot: 19)
<font color="red"> Hero bets for 16</font>, <font color="red"> CO raises for 32</font>

What's the plan?