Try these two forums
http://forums.jag-lovers.org/
http://www.jaguarforum.co.uk/

Cuddly,

Your basic answer is Yes you need to get more into the engine. In order to
replace the timing chain you will need to remove the head so you can get the
timing chain cover off the  front of the engine. All these XK engines are
basically the same from 1947 to 1987 with some minor changes over the years.
Usually you can re-build the water pump  yourself for far less than a new
one. By the time you are done buying the re-build kits for the carbs,
however, you will be better off having a shop refurbish them.  Especially if
you need a new matching dome and piston. Just the jet kit alone will run you
$60 per carb.  Then you have the butterfly assembly and seal kit which is
another $75 per carb.  Pertronix igniters are  for sale all over the place.
Make sure you get Positive ground unless you have converted. I bought my HT
wires from Magnecor but had to convert to the push in style rather than the
original screw in type.

There are parts suppliers all over the US.  You need to hook up with all of
them so you can shop for prices to get the best deal.  Don't discount buying
from the UK.  The shipping is outrageous but the difference in the prices of
parts makes up for it.  Besides, I get parts from the UK in 2 days.  It
takes a week from California.  From the sound of it you are not in any hurry
for parts.
Soon you will be like the rest of us and working on year 8 of a 1 year
project.

XK's in California is/was pretty good. Barrett's in New Hampshire is also
pretty good.  Terry's in Illinois is the best for engine re-builds and
parts.

Webserve