It wasn't as bad as I thought it would be I used a trans , converter and flywheel out of a 81 Thunder Bird. The 302 came out of my sons 77 mavrick the drive shaft is the didn't have to be modifyed. I had to fab a trans mount because the boss sits about 2" back farther than the C4 used the same starter.
I found a aftermarket trans mount and copyed it.
The biggest problem I had was I had to make the shifer linkage and kick down linkage work because I didn't want to cut a hole in the floor of the grabber but I got lucky and had a threaded boss on the side of the bell housing.
A c4 shifts backwards from a AOD.
If you decide to do this(MAKE SURE THAT AS THE THROTTLE IS OPEN THAT YOU HAVE PRESSURE ON THROTTLE VALVE OF THE TRANS{KICK DOWN LEVER ON THE C4} ) you can burn an aod up on jack stands if it's not adjusted properly or in 6 mile as a friend found out.
The whole job took about a saturday.
One more thing, if you have a/c trim the drain under the car because the bellhouing sets up against it and seals it.