i was woundering what the power limit the the standard ford falcon ba auto box can take cause im looking at upping the power to 250 kw and wanted to know if the driveline and box can take it and it is all natural power

250 at the fly or rear? Didnn't the GT's geet 290kw at the fly and the auto boxs handlee it and Ford's willing to warrenty it.

I wouldn't much worry bout it, seeing as, as twr7cx said, the GT's came specced with the same auto (I believe nothing was changed?).
To give you even more piece of mind, look at some of the E-Series guys (cough.. CHEF... cough) putting 200rwkw through a weaker box then your own.

If you can get an edit that upps the pressures during shifting it will make the box last longer. There is a significant difference in the shift calibration between the two boxes.
A trans cooler will also help. There are some differences between the V8 box and the I6 box. The case and output shaft is different. So is the a***, the V8's have stronger gears and slightly different ratio's.