It seems to me the bigger problem is NHRA running long. A few oil down delays could be a real problem.
ESPN seems to start NHRA whenever they get around to it, but never end it over the purchased time. If NHRA buys two hours, they get at most two hours.
When it starts late because something else ran long, sometimes NHRA is allowed to run long by the same amount, sometimes they get truncated to get the next show to start on time. I can't recall it ever running long without some rescheduled show in the next day or so (which I assume NHRA pays for).