Could slow you down too.....
I went the other way with the Kilgore 2.10/1.40 set and it is quicker than a 'glide, or the stock 2.48/1.48 gearset. It is not any of the trick light stuff.
Sometimes reducing the speed at which you accelerate rotating mass can take less parasitic loss and improve your ET. Usually that would be when you have plenty of HP and torque multiplication from your converter.