Gordon I could add on a little to what Bill says. I have not rebuilt a XK engine (yet) myself but have done a 4 cyl of very similar arrangement and is not all that tough and it is educational and rewarding. I farmed out the block machine work and valve train work to machine shop but did the rest of the engine assembly myself. I made a few mistakes on my first engine but 20+ years later have not touched the inside of that engine and it is still running strong as a daily driver. Mostly it depends on your circumstance and time frame you want to complete the job. First off you must have the time, space, basic tools, basic knowledge and energy level to complete the job. Otherwise it might turn into one of the common stories of a car that comes apart but never seems to get back together. My 2 cents
David Barnes
68 E-Type FHC