Thank you all very much for the suggestions. I hadn't tried the sources from hotrod lincoln or wdoftexas.
The rear end seems to be 1958 1/2 ton and a 10-bolt--as I counted them on the rear cover. The number on the front pinion bearing cross checks to a bearing for a 58 1/2 ton and the wheel cylinder cast # cross check to 58-59 Chevy 1/2 ton. So I concluded its most likely a 58 1/2 ton rear end.
I will admit my ignorance about the GM corporate axle and wouldn't know it if it was staring at me. On the rear end there are studs on which the rear cover mounts and studs on which the front is mounted and presumably can be removed. If both were removed you would be left with axle housings and a big round '0' in the center. Maybe I ought to do a search on this site for it and educate myself.
This site is a great resource thanks to the members.
Jerry
