Does anyone know of a serial number chronology of the major changes during the production of the XK8/R. Like the change to the 4.2 or the 6 speed auto?

 

At a high level, the parts manual is divided by major revisions:

www.sngbarratt.com

That is a start...

 

This might give you some additional information : Pages 6 and 7

https://www.limora.com/en/turn/pdf/v...le/507955.pdf/

 

Holy cow. This is amazing. How come I've never heard of this place before? Incredible catalogue!

 

Limora isn't particularly well-known - even here in the UK. However, it's a very interesting and comprehensive catalogue and, like S N G Barratt - is available as a "proper" paper book.

If you have a spare Euro15k or so, you can buy a complete bodyshell :

https://www.limora.com/en/british-ca...ell-69423.html

or maybe spend a bit less on a travel bag :

https://www.limora.com/en/warehouse/...-1-357180.html

(No personal connection or involvement, so I'm not getting any commission !!)