Well, its that plus the fact that the wires are coming out of the wrong place. The wires on the E-Body exit the motor housing near the shaft side whereas the after-market ones come out the side that will be in the engine compartment. Without opening up the new motor, I would not know if there is a channel inside to re-route the wires.

Even if I removed the plate, the E-Body motor attaches to the heater box by two screws on the motor itself so it uses no plate. This means the motor would have no way to connect to the heater box.

Could I get a new motor and put it into the old motor case? Maybe
Could I drill holes in the heater box plate and install the new motor into it? Maybe
Could I re-route or hide the wires so it would not look obvious from the engine compartment that I used the wrong part? Maybe.

If these are the only choices I have then I may consider them but I was hoping someone sells or rebuilds these so I can put it back the way the factory left it.