No stock GT500 including a 13-14 will trap 140mph! Not even close.At the winter nationals In 2008 , Ron Capps and John Force raced an identical pair of Shelby GT 500 as part of a promotion. Both cars were stock and John Forest was in the far lane and Ron Capps was in the near lane. I don't remember the elapsed time, maybe 10.80, but both cars ran 140 miles an hour. .... both cars were white with blue stripes and after that race I wanted a Mustang GT 500 really bad.......we had great seats in the top eliminator club....
They were on display for the 4 days and the final day, prior to the finals, they raced.....they were exactly like mine.....and we pics of both cars.....yes stock with SC and had some different tires I beleive....both cars 140 and we're bouncing off the Rev limiter at take off.....the signs near the cars said they were factory GT 500.....oh and the exhaust was off....forgot that.....I was in 3rd row and saw it....sorry, but that's what happened.....after the race, both cars we're autographed and towed to the drag racing museum in pomona, next to the hotel.....we went there after the race and both cars were on display outside as well, they had racing harnesses as well.
I don't doubt you saw it. There is still no way those cars would trap 25 mph faster.
A pro driver could clearly help the 1/4 mile time but he isn't going to coax the much additional speed out of the car.
Evan smith got a 2011 to a 11.8 1/4. That was typically .3 faster than anyone else. That is possible but he sure wasn't turning a low 10 second.
Again I am not discounting what you saw, I am discounting what you were told (that it was stock - minus the exhaust).