Yes your very nice man is correct. I was a young lad when x-flows came out and my best friend who was an apprentice Ford mechanic would regularly swap engine in Cotinas and later Escorts. If you think about it the engine in a Morgan is quite encased I compared to a Cortina, so problems when hot is not surprising.

If I recall correctly the engine block can get very hot especially if a tuned engine or if it is a hot day. The heat transfer to the carburettor can then cause the fuel to quickly evaporate in it and then it is hard to start through fuel starvation. I would look to replace the spacer between the carb and the inlet manifold with a modern material that has a high heat resistance. Have a look on Classic Ford race rally tuning sites I am sure they will be available. Also a reflective heat shield around the float bowl of the carb. between it and the block.

Another thing to check is the compression on the cylinders, they can be prone to valve seat burn and then the valves don't seat properly when hot. This can make hot start very hard. If compression is low on one it might be worth investigating. I would add that if you have a bad valve initially it usually shows up with an occasional mis-fire when running.

Hope this helps

Adrian

Buggered Off, to a modern none leaky car, heart's still ticking