BTW, You sure its not a valve cover leaking ? When you hit 6k the fan is blowing it off the head and onto the exhaust ?
With a PCV, when your at WOT it only sees low to no vacuum, with only one evacuation tube, you might not have enuff evacuation to handle the blow by. Ditch thew pcv and run a breather and see what happens, or ditch the evac tube for a breather. How tight is the motor ? If the blow by is excessive, nothings gonna fix it except a bag of cash.
Craig