The 5.4L DOHC 32V motor is available in the new 2003 Ford Falcon XR8 in Australia for 2003! This is essentially a 00 Mustang Cobra R setup. Ford says the 5.4 won't fit in the Panther because the engine is too wide. The Falcon is a much smaller car and it fits in their no problem. I think the 5.4 can fit without a problem in a Panther, the problem is Ford is also right in saying it won't fit bacause the Panther is a body-on-frame design and the manufacturing/assembly process suggests that the body go down on a frame with the driveline (and engine) already in place. In this case, the 5.4's heads would likely challenge the large shock towers and would be a problem (sliding one in afterwards from the top shouldn't be a problem but it just can't happen on the assembly line).
North America is supposed to get a version of the Australian Falcon sometime soon.
GEO