Top End Miss

You may want to stick a vacuum gage on the intake and watch it at the point where it misses. If it shows any vacuum try a larger carb. The power valve is spring loaded open, so unless it simply isnt flowing enough (usually a problem with alcohol carbs) it will be open at WOT. I'm more inclined to think it's a valvetrain issue. Now that you have the springs in, it might be a good experiment to stick .060 shims under the springs and see if it rises again.