Since you are after just "power" and not torque why didn't you keep the the 4" stroke crank and over bore .100 or .125" to get a bigger bore which would allow you to unshroud your bigger valves and make more "power"??
Since you are after just "power" and not torque why didn't you keep the the 4" stroke crank and over bore .100 or .125" to get a bigger bore which would allow you to unshroud your bigger valves and make more "power"??