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

I did some maths too. 400 Chev 4.126 bore, 3.75 stroke. 400 Ch 4.34 bore 3.38 stroke. One long, one short....stroke.
Piston ring contact area for both. Used 1/16" for both comp rings & 0.025" for each oil ring rail. A popular combo.
Swept area for Chev is 8.75 Sq in, 8.77 for the Chev. The reason they are not equal, but very close, is because the B & S of each to not calculate to exactly the same number.

Piston friction. With the larger bore, you have a wider thrust face on the piston, but it travels less distance [ shorter stroke ]. And vice versa for the smaller bore.
As I said earlier, I doubt there is much difference between the two, when all the variables are taken into account. There ARE a lot of variables such as piston skirt design, friction coatings etc, but if these differ between the two engines, then it is not an apples to apples comparison.