Yes Eric just did a 4.3 700R4, Dual case in his 87 Mini.
I would go with the 5 speed swap for the fact that if your starter goes out you can push or pull start it. Got me home from Colorado once like that.
If you do a 4.3 then I would say go with the 700R4 since you can do it with only the Tcase adapter. However since you have an auto you got a chain drive Tcase. That will need to be swapped also if you want 4.7 gears
Start looking for a Turbo 5speed and case. The swap has been done before.
