[drdisque]

it depends on the manufacturer, back in ye olden days, most manufacturers had 2 families of V8's, the ones with larger displacement and generally larger everything were the big blocks and the ones with smaller blocks were small blocks. However, displacement isn't the sheer determiner for whats a big block and whats a small block, for example the Ford 351-Windsor is a small block and the 351-Cleveland is a big block even though they had the same displacement.