I did one of these in 1990.  You can use the housing
from a Syncro transaxle, or what I did, is have a block
welded on to the side of the housing and machined
to fit the vacuum servo.  This route is a lot of work,
and dangerous, because it is easy to ruin.
The housing swap is expensive.   IMHO this would
be a lot less expensive to install a limited slip
axle from germany.   All things considered, it is
not worth it.
                                                     Eric

Bill Knight wrote:

> Jeff,
>
> Please tell us about the housing modifications you did for
> the locking differential.  I'm seriously considering this
> option when I do my transmission rebuild soon.  Would it be
> possible to simply use a cable mechanism rather than the
> vacuum control?  I'm not familiar with the details of the
> diff lock setup, would you please describe how it works and
> how it fits into a 2wd diff?  I'd sure like that added
> traction!
>
> Thanks,
> Bill Knight
> Raleigh, NC