@ Jimkron
Thats strange, you should see a change in revs at the top with an adjustment on the high needle.
Id reset the needles per the manual and make sure your fuel oil ratio is correct just to be safe. Also make sure your not running too hot per cylinder, 200F is getting hot.
You can also check your valve clearances so they are shutting completely because your peak rpm is low.
Try that then last resort is taking the carb off to clear out the ports and make sure there's no blockage.