If you find the head won’t detach from the block due to corrosion on the studs, some people have used a hydraulic jack between the oil filter boss and the intake manifold to loosen it, though I have never done that myself.
I had the situation where one stud on the intake manifold was so corroded it could not be removed, so I suspended the head dangling from the manifold on my hoist and kept putting oil and heat on it, took about 2 weeks as I recall before it moved.
Note the very tiny part numbers stamped on the camshafts, and/or keep the tach drive attached, so you don’t get them mixed up. Measure and make a note of the clearances and shim thicknesses, and keep each valve and tappet in its place. You may get lucky and find none need changing.
If it lived in a warm climate where they don’t use anti-freeze, you may find the coolant passages in the head around the steel head gasket are corroded away. This has been discussed many times on this and the XK engine forums. Basically the procedure is to grind away the corrosion to expose good clean metal, then immediately like within a hour TIG weld it with low heat and skip around, letting each place cool so it doesn’t get warped, then file off the excess. If you do it right it should not be necessary to mill the whole surface. People do that too readily.
When you get to the crank, note the condition of the split pins (aka cotter pins) on the rods. I’ve seen some engines where they were all in excellent condition, and one Mark VII where they had been wrangled by pliers, obviously used at least twice, and there were broken ones in that sump. I make it a rule never to reuse an old split pin (i.e. penny wise and pound foolish).