Keeping a “spare engine” would greatly reduce the down time of the car.
If you have your motor built and checked out (already run on a stand, and even dyno’ed), then pulling your original, and installing the new engine COULD BE done as a long weekend job!
Note I say “could be”….
Nevertheless, building a complete replacement certainly lets you build your motor with a more relaxing timeline!
Thats what I have done, and at this point, I don’t swap as many of the accessories. I think I keep the flywheel, intake manifold, heads, oil pan, and perhaps the water pump on my spare…
Rocky