So can I put a 2003 jaguar s type R supercharged engine into my 2002 s type 4.0 v8?

Not without a lot of work that would cost a fortune, it would probably literally be cheaper to just buy an S-TYPE R in the first place ?

To do it right, you would need a full car as a donor anyway, not just the engine.

The 4.0 V8 is the first generation pre-facelift model, the STR is only available in the post facelift version, so there are a lot of other differences other than the engine.

You would need the brakes, suspension and gearbox swapped as a minimum, you would then need an engineers report for the car to be insurable and legal on the road.

 

 

You might be better off with an earlier 4.0 engine from an XK8, like this one, which seems very cheap at £675 or offers:

https://www.ebay.co.uk/itm/284331537207?hash=item42337af337:g:MvYAAOSwXs5gxiqH

An absolute ton of work as Jon suggests though. Hope you're handy with the spanners and have good facilities as this is not likely to be something viable to pay someone to do for you 😉