[willyc]

I'd call but it's close. If you're ahead on the flop he's got 12-14 outs, and if you're behind you're drawing nearly dead. You need 30% equity to call and I figure you have a bit more than that.

Board: Jc 7c 3c

Wins Ties Equity
63.61% 1.57% 65.18% ( 33,77,JJ+,AcKc,AcQc,AcTc,KcQc,AcT+,KcJ,QcJ,JTc )
33.25% 1.57% 34.82% ( KdKs )

If you add more random made flushes to his range then it's a lot closer but I think you're still OK.

Board: Jc 7c 3c

Wins Ties Equity
68.43% 1.35% 69.77% ( 33,77,JJ+,AcKc,AcQc,AcTc,KcQc,AcT+,KcJ,QcJ,JTc,KcT c,QcTc,Tc9c,Tc8c,9c8c,8c6c,6c5c )
28.88% 1.35% 30.23% ( KdKs )