Yes you can. But BTW Posi-trac is a GM name. Ford used Trac-loc [img]/forums/images/icons/smile.gif[/img]
There are many difrent typs out there, Lockers, clutch type limited slips[like the OE one] Air locker, gear type, etc. Now what is your use? Just a little more push? I would stick with the OE type. Probably get one installed for a little over $600.
If you want to shop a bit, pick up a 4wd mag. All kind of ad's in them for difs.
The Trac-loc and Powr-lock are from Dana. One is a limited slip, the other a posi. Both are clutched units. Jeeps used Dana diffs and axles a lot. Both units were available for years in the Dana-27, 30, and 44. They have them for the Dana 60's too.