Here is a YouTube video showing the details of a 1978 Jaguar XJ, which happens to be a coupe, and also has a 5.3 liter V12 engine.

There are many 1978 Jaguar XJ6 in the U.S., and there are some 1978 Jaguar XJ12, but not very many two-door coupes.  This video made in Great Britain, shows a rather rare vehicle, because of its configuration.

I have shown this YouTube video of a V12 Jaguar, and also another YouTube video of a V12 Jaguar recently, because you will never see cars like this anymore.

Here is this same 1978 Jaguar XJ 5.3 C V12 two years later, after it had its steering, suspension, and brakes upgraded: