[Lincoln]

My previous employer, who manufactured medium-to-large industrial stationary type engines (up to 30,000 horsepower), had a policy to always store their crankshafts vertically as lying them down would "permanently" distort the throws even with the main bearing surfaces supported properly. So they were stored vertically with the flange end supporting it. No doubt the design and length of the crankthrows, between the mains, contributed to the flexibility of the shaft. These were one-piece forged steel crankshafts and could stand up under the rigors of almost continuous operation for many years, but they had to meet certain requirements on what was termed "crankshaft web deflections". Service conditions as well as how they were stored all affected "deflections".
Considering the shortness, and "apparent stiffness", of the Ford's crankshafts, I would not think method of storing would be important - as long as they were stored without supporting something heavy!