You're more than good to go. That PSU will likely even support 2 GTX 770s.
However the PSU only got 40 amps per 12v rail, but I don't suspect it will let you down. Antec usually make some decent PSUs. A guy on Newegg mentions that he can run two GTX 570 with no issues whatsoever. GTX 570 uses more power than a GTX 770, so as mentioned before, you're pretty much good to go.