INSTR fuse blows when I start the engine

I hadn't considered that there might be a difference between the original and aftermarket connectors. I will compare it with the service manual diagram.
Easiest way to rule my experience out... Disconnect the aftermarket replacement ignition switch, replace the blown fuse, and pull the lights on. If everythings good except the column mounted shift indicator, there's your sign.
At that point you would use a test lamp to determine which wire in the cars harness connector is hot only when lights on. That's the one that the orange wire connects to.
Good luck