Parts swapping is parts swapping. I would be fairly comfortable swapping motors -- in a sense it's not so different from changing tires.
But an outright rebuild, or, the installation of one of the big valve heads or the big bore kit from Procycle would be different.
How difficult is the build, and what special tools are needed, for those chores?
'00 BMW R1100RT, Gone away: 5 previous BMW's, 3 Honda's, 2 Suzuki's
"The object of life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane." - Marcus Aurelius