the REAL difference between big blocks and small blocks!!!
Big block and small block are terms that only really mean anything in the world of chevrolet. Small block was the family of engines based on the 283, big block was the family of engines based on the 396 (or 427, not sure which came first) Untill recently any chevy V-8 was either a big block, or a small block.
Ford on the otherhand, has many different families. The flat head, the Y-block, FE, MEL, windsor, 335 series, and 385 series.
Those that say it cant be done should say so quietly, so as not to disturb those who are doing it.