Here's another option for you to consider for a 4.0 XJ cam. The original cam, in my 88XJ, have dimensionally wider lobes than the narrow lobes on the newer cams. Jeep engineers designed the wider cam lobes for a reason. Likewise, there have been many threads showing the lobe thickness variations between the older and newer cams. I wanted to use the wider cam I had, so I talked to Comp Cams about regrinding my original cam. I sent them my cam for inspection and then we talked about what "grinds" could be done to my cam to get the torque vs. RPM where I wanted it to be. It worked out perfectly.
Best regards,
CJR