I have an 03 x type with a great motor 3.0 I also have an 03 s type that I want to put the motor from the X type into the s type but the s type is a 4.0 will it work

Yes and no.
Yes it will fit
no it wont work, you have a v8 and electronics and exhaust etc all totally different and not worth the hassle. Plus you would end up with a night mare. Now a ls chevy engine swap has kits out there or just get another 4.0

If the S-Type really is 2003MY then you should have the 4.2 engine???

bob

Good point.

Still not viable to put an engine from an X-Type in.