Torque is created by displacement, which is bore x stroke, yes longer stroke has larger multiplication factor but what is it multiplying, the forces from the piston created by the psi of the combustion, larger piston more force to be multiplied. So bigger bore more force applied to the crank short stroke less multiplying
Smaller bore less force applied to the crank but longer stroke more multiplying kind of equals out at same displacements. (energy cannot be created or destroyed)