Look at it this way, the e.t. tells you how well all the mechanical pieces work together to get you from point A to point B as QUICKLEY as possible. A highly efficient drag chassis, well hooking tires, great weight transfer, high stall convertors, steep gear ratios all equate to low e.t.s.
The m.p.h. tells you the horsepower of a particular combination and the trap speed, which is calculated over a set distance at the very end of the strip. How FAST this section is run equals horsepower of the engine less any losses from convertor inefficiencies, parasitic drag, heavy wheels and tires, etc.
Of course this is all prefaced with the assumption that the driver stays in the throttle all the way through a run. You ever watch the races when a top fueler blows the tires into a cloud of smoke a 300 feet out and still run a 10 second e.t. at 60 mph? How about a bracket racer that runs a 15 second e.t. at 115 mph in 2nd gear? In the simplest terms, elapsed time is mechanical efficiency and miles per hour is horsepower.
