Two become ONE!

 I measured the two halves and used the dremel to cut the rear donor car's front and top off.

Then did the opposite for the "front donor" car.

Used a grinder to level the rear door handles...

And then used body filler to "erase" the rear doors all together.

After a little sanding...

I glued both halves into place on a steady board and put tape over the seams to keep the J-B Weld from oozing through to the visible side of the car.

After the epoxy sets, I'll use more bondo on the outside and cut a line for the the rear door.