Hi, I have a 2002 Jaguar XJ8 Vanden Plas. Pretty sure im needing a mew engine. Have looked for and low for one. What would be the years that I can use? For example: I found a 1998 XJ8 4.0 but im not sure what the differences are and if id be able to make it work. Thank you!

 

You need to look for an AJ27. An AJ26 (early engines) are slightly different. The ignition is with 2 pin coil over plug units rather than 4 pin. It has IIRC less sensors. I think AJ27 in AJ26 car was easier than AJ26 in AJ27 car.

Others will chime in.