Possibly the most common mistake I see when deadlifts get heavy is the bar drifting away from the body.
Many lifters assume that a deadlift is just picking the bar straight up, but this isn't effective. As you pile on the plates, you need to think about actively engaging the lats and pulling the bar back into your body so that your weight shifts backward slightly.
Keeping the bar in tight helps ensure every pull is smooth and efficient.
Didn't it seem that the bodybuilders of yesteryear had bigger chests? (We're talking chest circumference here and not pec size, mind you.) Ellington thinks so and he knows why - it was all due to the all-but-lost art of ribcage expansion.