It all comes down to meeting the "right" guy. Over 30 yrs at the drag strip off and on and I've seen built 340's with 4.11 gears choke a mid 14. I also seen next to stock with 3.55's go mid 13's. I think it comes down to if "a guy" knows what to do and if he can tune. I've seen a few "mild" 383's in A-bodies run mid 11's. If somebody can't get a 383 to run, or a 360 for that matter, it's on the owner.