I'm pretty certain that the PSU will be fine with 600w, but I'd like to know the model and make. I'd recommend getting a 990FX board since they are better for overclocking and are usually better quality/more features on board. If you are going with a GTX 970, I'd recommend you to go the i5 route since there will be a potential bottleneck on the FX-6300.
For example, an i5 with 970 will yield more frames than a FX-6300+970
Intel's single threaded performance just outclassed AMD's and Single threaded performance is still important in gaming to this day. Games are just starting to utilize more cores and the i5 is just overally better than the FX-6300.
If you can push for a 8320, it'll alleviates the possible bottleneck.
I'm pretty sure the FX-6300 will do alright, just that you won't get the maximum potential out of the graphics card with it.