My 2000 XJR needs new heads, the car overheated and the heads warped, I found one for the right side on ebay from a 1998 xjr but don't know if it will fit my 2000. Are they the same? Any variations between model years? Any compatibility issues?

 

ALL 4.0 cylinder heads are basically the SAME!!!!!!!!!!!!!(AJ26,AJ27,AJ28)
There are differences in Camshafts and Lifters, but they will all bolt up and work.

Be aware of the major difference between NA and SC.

bob

 

You don't need to go for "XJR" cylinder heads. Heads from XJ8 3.2, 4.0 or S-type 4.0 (not from any 4.2) are all the same as long as they carry numbers XR83-6C064-xx for left and XR83-6090-xx for right. It is actually better to look for heads from an NA engine as they would have been stressed less, especially if from a 3.2 XJ8.

If using a head from an NA engine, you only need to plug one oil passage at the front of each head for which you can get special rivets here:

Amazon

Amazon

. The position of the hole to be plugged is shown in the attached bulletin which just shows the operation the other way around - removing the rivet.

 

Thanks, those part numbers help a lot.
Do those plugs just thread in or do they also need to be welded?

 

The plugs are actually blind rivets. You need a heavy duty rivet gun to install them, i.e. a rivet gun which can take rivets having 3.5 mm pulling rod. Something like this: