I was looking for this post the past few days.
Let me help on the better et=lower mph. Generally you can say better 60’= a lower mph. When spesking about most cars. Here is why… most time in big hp cars they will spin off the line. This effects the mph by increasing the mph…once the car catches up with the spinning tires the result is a better mph… spinnig off the line will help get the speed up faster…The spinning effects the 60’ because your spinning early on…when the tires bite hard there is no wheel spin and no time loss every inch of 1/4 mile is acceleration down the 1/4 mile.