My engine builder never does it ..but then again, he assembles them ..and then parks them (with the valves loose and in a plastic bag) until they're being installed in the respective stock car/bracket racer. My only thought is that you would not want to mess with the static lube film that's in there. He stores his on their end ...but I always thought it was for saving space ..but it could be to leave the bearings unloaded
..never thought about it much.
His main concern, which has substantial merit, is the rusting of the open valve cylinder. I've taken many a block with him to the car wash (before he purchased his own pressure washer) to clean out any honing and other machining debris out of it. Before we could return to the shop, you could see rust formation on the cylinder walls (amazed the heck out of me- perhaps it was so quick due to the fresh hone job just done on them
).
I don't know how often that you would do something like spinning the oil pump ...but if I were going to turn the crank ..I would try and do both at the same time. This would re-oil the cylinder walls and refresh the oil film in the bearings. I would guess a seasonal spin of both wouldn't be too little.
Aside from assuring that you minimize the moisture infiltration, all this may be along the lines of vitamin therapy for a future heavy smoker that eats bacon for breakfast every morning. That is, the insult of running the thing may make your "in stasis" storage methods a moot point.
But it surely can't hurt...
