Interesting question Scott. I googled it several ways and found lots of conflicting information. A couple of sites (including the Wikipedia FE engine entry) indicate the Y-block, Windsor and Cleveland as "small Block", the FE series as "medium block" and the MEL, 385-series as "big block".

So would it be safe to say that it has nothing to do with CI and everything to do with actual block size? I'm confused now. Need more beer....