Check the motor height on that K line GG1 - I wanted to do an EP4 on a Williams GG1 - the older ones have pretty tall motors (but I think the recent ones have much smaller motors - I may be back in business). Was gonna rig something up using either a modified EP5 shell from a lionel or hack up some F3 shells. The nose/window height on the EP4 is tighter than the F units - wasn't sure exactly how to work that. Maybe 3D print.
Jim