new diff gears same times

hi everyone. i just put new diff gears. i went from standard 3.23-3.55. the car feels quicker mainly down low but at the drags, the 660ft mark they are a tenth better but by the 1000ft mark they are slightly slower. the car is doing about 5000rpm in third over the finish. the only thing i can think of is the gear changes
in the auto. has anyone else experienced this or no why it is happening. could it be something to do with the computer? any advice would be great as the gears
are getting changed again because they came out of another car and are noisy.
trying to decide between putting standard gears back in or forking out 500 for a new set