One thing leads to another... mean 318?

I'm not following you.....
I know there's a secret in your question; but I'm just not seeing it.

What would happen if you took all the 340 stuff and slapped it onto a 360, at same as 340 cylinder pressure?

Or how about a 383Magnum with a 440 crank?

or a 318 with a 4" arm

Would a identical built 340/360 have the same cylinder pressure ??

and if they did stock bore, 4.04" vs 4", the 340 piston would have more surface area so it would have more force driving the piston down, if both where stroked to give each the same displacement the 4.04" bore would have slightly less stroke multiplying the slightly higher force, which should theoretically equal out. But since they don't have same displacements 340 vs 360 and at similar VE% the 360 will have less force on the piston but have lot more multiplying "stroke" on that force, ie.. more displacement more torque. Not cause of stroke cause of overall displacement. But that is obviously just torque, so yes an increase of stroke on any given bore is gonna increase displacement ie.. torque but keeping everything else equal is gonna decrease powerband rpm, which should put you at similar hp output.

So how does stroke in it's self increase hp ?