I'd like to add to the discussion.
1. If a guy had a 400 block and a 350 crank laying around it would make perfect sense to put the two of them together. If he needed something to occupy his time.
2. When the machine shops in your area lack the capacity to provide proper machine work it makes sense to use a crankshaft that will require no special work to be done on the rods for them to clear the oil pan, block and camshaft. That is if you have hefty rods with large bolts.
3. In spite of the fact that I own two 400s, and love the torque, I really like to hear short stroke engines scream in a 4-speed car.