I am looking at buy a 1999 XJ (jumping into Jeeps after I sold my CJ-8 years ago), and I ran across a strange VIN. The VIN is 1J4FF68S3XL535621 which seems to follow the 2000-2001 pattern but not the 1997-1999 pattern. Anything to worry about here? Any advice would be greatly appreciated. Thank you.

 

Probably a late build 99, using the 2000-2001 style VIN setup. I wouldnt worry about it. It still comes up as a 99.

 

Do the late build 1999 have the 331 head casting or was that specifically to the 2000-2001 - that is what I was more concerned about.

 

Dont know. Check the driver side of the head. The number should be visible just below the valve cover, between cylinders 3 and 4. Like this.