No way you can crossfire two 270x and run a 9370 on a 650 w PSU. That processor has a 220w TDP, not to mention the water cooler. I'd get a 750-800w certified psu.
Providing that you do not stress your hardware under a synthetic benchmark, a decent 650W would be all you need for crossfire. Games only cause GPUs to use about 2/3 of their total power draw. I would get 750W to be on the safe side.