Ok I have it turns out an AJ27 4.0 (non supercharged) on my 1999 Jag Sovergein (XJ8) .
I have to replace my engine as its blowing oil in air filter so either I rebuild the current unit or fit a replacement engine in the car and rebuild the orginal at a more appropriate time.

I will only consider a replacement engine with steel liners, non-nikasil, so I need to figure out what other jags can supply an engine as a donar car..

I just want an easy direct fit, no changing anything really.

My question is will an AJ27 4.0 from an S type be identical to my engine and fit seamlessly? Some threads here suggest its the same engine others that it isnt interchangeable.
If i go for x308 donar car i understand it will need to be post August 2000 as thats when the steel liners came in.

Its just not that easy to find an x308 here in Australia as a direct replacemnt from so thats why i am enquiring in regards to a the S Type as they are more common.

Advice is appreciated.
Best Regards
Peter