I think this is right place to post my query .Well, I would like to know if it is possible to apply a superchargerin either XJ40 (4.0 liter) or X300 ( 4.0 liter) pre 98
May be buying an XJR is a better way to go in regards to performance but you know XJR comes with the firmer suspension wich I don't like yet I don't like the blackish woods over walnut or burr walnut .
I like chrome and walnut trim and these two are must for me .I think XJR's supercharger can fit in any Jaguar but guru know better for sure

 

Well if it'd even bolt up correctly, you may have to fabricate and run new oil feed and return lines and maybe the water/coolant too if it has them, I know more about turbo's then superchargers but just a thought that covers the basic principles. Drive belt alignment may be an issue too, pulley sizes maybe, not sure you'd actually have to attempt it to find out first hand.