[jclark003]

If your engine has a knock sensor, a misfire in the engine can cause it to roll back the timing, giving you a lazy engine that will not reach full RPM under load. As previously posted changing plugs and or wires may clear things up. Also Your port tach bouncing around with no noticeable change in engine pitch points to a possible coil or tach issue. swapping the tachs from the good engine or the tach leads followed by the coil may help isolate things. The falling off at high end could be Restricted fuel delivery from a plugged filter, stuck anti-siphon valve or weak fuel pump.

Good luck and keep us posted