I would say yes, but I wouldn't go crazy with any overclocking. Your 12V rails can give you 46A (552W/12V = 46A). I will give you a warning, I went down this path and had HUGE heat issues with dual 4870's. The top card would overheat and top out over 100C. I see you have (4) PCI-E x16 slots. In dual card config you get 16x+16x. If you have to use the top two slots to get this there is not much room for air to flow. However, if you can use the 3rd down slot, you will have less heat issues. Just a fair warning.
But to answer your question, yes, the PSU should work. I just wouldn't put the additional load of Overclocking on it, or at least any crazy OCing. I am pretty conservative with my power, so to each his own. I just know what happens when you over work a PSU. Bad Bad things can happen.