If this is the PSU you're referring to,
http://tinyurl.com/6fgv5fp it has 3 PCI-e connectors that are compatible with both 6 and 8-pin PCI-e.
"What gpu are you using?"
The OP said the PSU is to power a GTX 770 in his first post.
While the Antec High Current Gamer 520W is also built by Seasonic, if the OP can spare the $5 to go with the 550W unit, he will get 5 more amps to work with on the 12 volt rail.