Pointing out the HUGE fallacy with your premise.
From the factory, as a regular joe could buy them. None of the A cars ran better than 14.20's in purely stock form. No distributor recurving, jetting/rod changes, lowering, drilled shocks/shock packages, lightening or any of the other tricks that were done by the cars as tested.
As pointed out earlier, when was the test run, middle of the dog days of summer or on a cool crisp fall evening/day? Nobody really gave much thought to DA in 1968-1971. Test at OCIR then at Las vegas and see how that fast car runs .4 off.
Post bomb away... more written east coast diarrhea to follow. Bandwidth killer!!! :D