Thanks for the reply Don. The reason I'm asking about this is I seeem to recall (memory is the first to go!) seeing a diagram showing how to ID the different differentials by either the shape of the cover - OR - the style of rear hub assemblies in a vintage Chev parts catalog or the shop manual reprint. BUT - I can't find the source of this 'memory'!! :o)

Thanks again Don and thanks to anyone who has additional info -
Keith