New FB owner, project, teardown, and questions. Pictures too.

[N.RotaryTech]

Update, what I'm doing today.

So I recently acquired an FB front cover and engine-mount brace, drive-shaft, and a junk transmission.
I start with the drive-shaft to see if it will bolt up. It doesn't.
And now I'm confused.

The plan is to use an FC S4 trans.
I thought that the FB driveshaft would work. It fits the FC trans but not the FB Diff.
So I gather all the drive-shafts I now have, and do some fitting.

In the picture below: the top drive-shaft is the FB, the one in the middle is the FC, and the one on the bottom is the one that came with the V8 "kit".

The only one that bolts up to the Diff is the one that came with the V8.
Another angle of the drive-shafts.

From left to right: FB, FC, V8 "kit".

So I start to wonder what Diff do I have?



Then I wonder if the part on the Diff that the drive-shaft bolts up to(is this called a flange?) is interchangeable?

Maybe I could swap the right FB flange in there, so I could use the FB drive-shaft.

Or my other option would be to cut both the FB shaft and V8 shaft, get the right combination from both and make one shaft that will work.
Ill have to send these off to a drive-shaft expert to do this though.

Any help/ideas, on this will be appreciated.