They are terrible in comparison to the guys with the sport 500s. Also there is chance he was granny shifting versus the sport 500 guys. There is alot more factors to think of
1) HE could have been runing lower boost 2) HE could have had lots of traction problems 3) He could have been stepping out of his power band between shifts.
Add a small shot of the hole and he could hit 1.5 60' foots.
Remember in drag racing its alot about the driver and traction and then horsepower. If you sit and spin you are not going fast and if you sit and bog you have alot of lost time to make up.