[xorbie]

Assuming your flush draw is good, which seems likely, and assuming worst case scenario that he has AA, and you have only 7 outs, which is about 6:1 against to hit. You are getting 2000:300, or almost 7:1 in combined pot odds and implied odds (this is assuming you know he will push the river). So it's slightly +EV. That said, there are reverse implied odds to consider if villain is pushing this river 100% of the time and either you hit a two or a board pairing diamond.