No, it won't fit. I already tried doing that on my 6800, but it was not possible to fit the card in the slot, because the cooler was too wide.
Sure it will fit


But it did take some moddin'


Some aircooled results from yesterday evening. Normal room temp and wasn't pushing it too hard yet (no artifacts etc).
GPU 0.15V over default, MEM at default volts.

Mark05:


Mark2001 (notice the low FSB):


some pics of the aircooled system: