Good article on basic stroker theory
Well the key to making the power is in the combustion chamber, with my limited knowledge on cars I still know that the root of the power comes from the explosion in the combustion chamber and how much fuel/air gets in there. If the piston gets forced down an extra amount due to the longer stroke that really has no bearing on how much power that explosion creates, so one could argue that a longer stroke doesnt really have too many benfits other then increased torque but with a sacrifice in RPMs. But like I said im no engine expert or engineer.. it just seems to make sense to me when thinking about it.