It's prolly not out of the question. It might be kinda rough with stock cooling.
The 9800 pro clocks are 380/340
The 9800 xt clocks (I've read) are 412/730
It doesn't look like it would be too hard to get those speeds. The oc on the core clock speed would be just under a 10% increase in clock speed. OC'ing any card, I've heard you can safely bet on getting an extra 10% boost in core clock.
The memory I'm not sure of. I don't know if that 730 figure has been multiplied out as in, 365 ddr (x2) memory clock = 730, or if the clock speed is really 730 ddr.