A buddy of mine used a fan out of a Lincoln once in is 2.3L. The fan wasn't powerful enough to keep the engine cool (and I think it was the same part number as the taurus fan). Granted, he could have installed it wrong, I'm not sure, but it constantly overheated.
I would recommend buying an aftermarket dual e-fan to ensure you can keep the 4.0L cool.
Had to use a Flex a lite 1250 cfm fan with the temp control through summit due to space limitations, worked great so far for the last 3 years and the engine temp barely gets above the "a" at the bottom of the temp guage. Guess having a 4 row radiator with the V8 kinda helps also.