360 stroker how much HP is picked up if everything else stays the same?

The engine with the longer stroke will have a smaller bore, so it will have less friction from the smaller contact area of the rings against the bore. I doubt there is much difference between the two. Where the longer stroke engine gets it's reputation for more friction is from the side loading; if longer rods are used to counteract this, then it levels the playing field.
Dragging the ring over a longer distance, will result in more friction , than going to a bigger bore for the same displacement.