Actually had a thread on this. I realize that in a 4-3, the DE's are not DT size, but they still make contact with offensive tackles on every play. I didn't actually compare the size of our d-line vs their d-line or anything like that. I compared our o-line to their d-line, and our d-line to their o-line. Our d-line is within 5 pounds of their o-line on average, and in a 3-4, that's still a big deal because majority of the time in a 3-4, the d-line is going to lock up with o-linemen, and play 2 gap technique (clinch on the linemen, read where the ball is going, make a move and hit a gap to get into the backfield). Our nose tackle (Melvin Lewis), is also 60 pounds heavier than South Carolina's center. Matt Elam, the backup, is 90 pounds heavier than their center. Considering the weight discrepancy there, and the fact that the nose tackle almost always plays the 2 gap technique, he's going to have to be double-teamed every time, and from time to time, the 2 offensive guards will have to double-team him while the center snaps and pulls, otherwise, he would get into the backfield too fast. That NT vs C match-up is the most intriguing one, because it's not one that USC had to really face much. In a basic 4-3 package, the center would either block a DT, or a linebacker (depending on whether or not USC is running with a fullback). It allowed him more opportunity to pull without plays being busted up quick. Now he's going to be lined up head-to-head on every play.
I would certainly give UK the advantage here.