Thanks, I also should've asked for any opinions on which would be more recommended - the 135k '01 from an XK8 or the 89k 99 from the XJ8? These internal items vary between the 99 & 01?

 

You should have it out in a day .I would pull it with the gearbox if we are talking the scrap car . More care needed on the XK8.You did not say if you have any lift. At a minimum you will need some big ramps and a rattle gun+ engine hoist.
Dont make the mistake of another member ...Put the manifolds on before you put it in !!