Yea, the RX360 would be the ideal rad for this setup. However, the RX360 kit plus a 6970 block will cost you about $300. I would recommend starting with a cpu only loop and then later add another rad and gpu block.
That's still a ton cheaper than buying all of those parts individually. Heck, it's hard to get a pump/res combo like the X2O 750 for under $100.