Also will the supercharger from a 4.4 fit on the 4.0? If so what do I need to do to make it fit?

 

look up "4.2 Gen V Eaton"

pretty sure it's just the intake gasket and another tiny thing

 

I just did the swap to the 5th gen Eaton M112 supercharger from the 4.2 models on my '99 4.0 L engine. It is a plug and play job, you just need the newer intake gasket covering the protruding bearing covers of the 5th gen supercharger.

 

@iDon

I am in need of a Supercharger rebuild on my 2001 XJR. What are some of the main benefits of swapping for a 4.2? Is it purely extra performance or does it also help with longevity. Additionally, does doing the upgrade put additional strain on the 4.0 engine. Please do advise at your earliest convenience.