Thanks Hotrod!

Doesn't surprise me after all these years---- but it does explain why the gearbox and rear end #s don't match anything in the Chevy manuals. I have a 3 speed gearbox with serial # CBJ105999 and a rear end stamped HOA0225. That ring any bells to anyone?
Gearbox has a GM 48 large casting #

Any help would be much appreciated.

Thanks guys