Any reason the GTX480 waterblocks won't fit these cards as far as anyone can tell?

Im looking for an excuse to buy one and I can get a 480 block cheap. I'm most defineately waiting to see how the 6970 pans out but I'm tempted to once again go Nvidia for a couple relavent reasons (namely noticeably better performance at my resolution and better performance in a few games I invest lots of time in ). Given the 480 seems to do a good 25-30% more than the 5870 at "1680x1050" plus it scales better with clocks / cooling, I'm hoping the 580 continues this trend. Sure some may say thats overkill but I personally enjoy 120fps gaming over 60 so to each their own.

Now as for a $600 price tag, unless Cayman is garbage I don't see this price holding up for long. I hope to see it replace the 480 in price which should be considered reasonable all things considered so far.