I made it over to Hot Rod Jim's tonight.
I explained the whole thing about the motor and transmission NOT ACTUALLY FITTING IN THE CAR!
He figured the easiest thing to do it trim down the coupler parts.
This is an advantage to Lovejoy couplers- they are two part, so you can replace just one side or the other, etc.
Jim carved out the welded-in splines, pulled it out, trimmed down the whole Lovejoy by about half an inch, carved out the inside a bit more, slid the splines back in and welded it.
Then he did the same thing for the other coupler half.
I pulled the entire commutator end of the motor off. Jim is going to take it in to his day job and mill the whole thing down. They have a mill there that can take off two inches of steel at a time.
I still have to chop off the pilot bearing tip on transmission #2, which is still in the car. That should be fun...
I will also have to get some shorter big metric bolts to remount the motor directly to the adapter plate as we will no longer be using the spacers.
I'm out of town this weekend, so no more work on the car for me.
I'll just have to work on the camper instead...