Just wondering it it has enough power to do 7 of them all overclocked.
Definitely not. Even before overclocking, we're looking at about 150~170W per card, or 1050W to 1190W. No headroom for overclocking and any derating in capacity due to the PSU heating up. Even if you clock them so that it can just about handle it, it's not going to last very long running at full load 24/7.