Learning NL 1/2

[Schizo]

1/2 blinds 200 stacks all around

I have 6 [img]/images/graemlins/spade.gif[/img]7 [img]/images/graemlins/spade.gif[/img]

MP opens for 10. I call OTB and the flop is:
K [img]/images/graemlins/heart.gif[/img]8 [img]/images/graemlins/heart.gif[/img]4 [img]/images/graemlins/spade.gif[/img]

I have a gutshot. Villian bets $15 and I?

Who calls here? A gutshot needs about 10.5:1. So in order to call don't we need to makeup an *average* of $160 on the turn + river?