Will this work?
 

As you know...
I stripped the rear gears completely a few weekends ago and am deciding whether to buy a completely rebuilt axle, have mine rebuilt, or to go to a junk yard and gamble that I am getting a decent piece.

It is a 12 bolt rear with 3.42 ratio out of a 71 K5.
The reason for this post here...
My father has a 78 scottsdale 1/2 4x4 pickup sitting in his field for the past 10 years since the transmission went. I am pretty sure this is a 12 bolt as well. According to my small amount of research, this may be an even swap. My blazer came from the factory with a Posi, is it possible the truck axle has one too?

I'm looking for opinions and advice here. It's $700 to have mine rebuilt (more if the posi is shot), $1295 to buy a completely rebuilt one, and free for the other one, if it will work and if it is in decent shape, but I have no idea how long that will last.
Thanks in advance...
-Tim

Well it turns out the whole thing is junk, including the posi and axle shafts. The PO hadn't had fluid in the rear for 5 years, the insides look like it has been sitting at the bottom of the ocean for years. The gear shop is going to media blast the whole thing, inside and out, then rebuild the whole thing with a new eaton and upgrading to moser axles. The gears are 3.08s and I'll stick to that since I've got the granny gear in the SM465. Breaking the bank big time but still cheaper than going to Boyce.