20 years ago I had a mk2 that had 3.8s on the back it was not a stype looking back you would think it had been added but back then a couple of guys said if you ever want to sell --- and they new jags it had amazeing power I sold it to a car yard sight unseen he had been told about it no one ever said anything to me but one guy who came just to see if it was still there raced down and bought it I have always wondered about it as I new nothing about jags then

 

Mine says "Jaguar 3.8s" on the trunk. It is surprisingly quick, for a rather large heavy thing. The Mk 2's had spats on the rear wheels and a solid axle, S-types had a bit larger trunk area, independent rear suspension and inboard brakes.