Just to follow up, I went to car-part.com ( the hyphen is important ) and lucked out. I found an Eaton carrier with 4:11 gearing from a 1972 C30 at a salvage yard a few hours from my house. I was cautious but measured everything and it seemed identical to the stock unit. It was not cheap - $400.
It bolted right in, was to a tighter spec than the original unit (lash, mesh and everything was adjusted well)and after a few test drives it seems to be working great.
I snapped a few pictures while I was in the process of cleaning it. Here is the original in the rear end so you can see the bolt pattern and so on.
http://i289.photobucket.com/albums/ll204/unclewes13/carrier0.jpghttp://i289.photobucket.com/albums/ll204/unclewes13/carrier01.jpghttp://i289.photobucket.com/albums/ll204/unclewes13/carrier4.jpghttp://i289.photobucket.com/albums/ll204/unclewes13/carrier3.jpghttp://i289.photobucket.com/albums/ll204/unclewes13/carrier2.jpgThanks for all the help guys!
Wes
