This is a great article on the differences between the 4-3 and 3-4 defenses. Before you dismiss this fanshot, consider these items as it relates to the Cowboys: 1. It is clear that the Cowboys were undersized as far as the 3-4 went. 2. It is very likely that Shariff Floyd could have been a defensive end under the Cowboys 3-4 and the scouts likely had him fingered for that position.