the last time i looked under an XJ hood, realistate is pretty scarce.... id look for a hole thats near the belts first.... with a cerpintine, you probably end up welding a ve grove to one of the existing pullies.
you would have to do some research to see if the volume of that pump is anything comparable to one of the larger yorks. i believe there are 3 sizes- its been a while since i have read up on them.