If you put the CG of the short block on the CL of the head it's easere to rotate the engine while working on it. If you're tip heavy or bottom heavy it will tend to flop over when you loosen or pull the pin on the head.
Not sure what all this "upright" and "sideways" talk is about. I've never used or seen this typr of engine stand used any other way than mounted to the back of the block.
DG
