Ok good enough at typing about geting a bunch of free parts and still not capabel of figuring out a RPM340 heads architecture? Lets see if i can help you with understanding,worst case scenario i may dig up some old pic of them and draw some arrows on it.
The part of the decksurface of that head that is closest to the port,valve and valveseat is not going to get any closer to the mentioned architecture by cutting the head .060 to turn it into a somewhat closed chamber,you may or may not know something about other heads but that head is what it is.