Why a Reverse Valve Body?

I was at a dealership (70ish) when the first manual valve body modification came "mimeographed" into the shop.
To my knowledge it was a Mopar mod, was definitely Reverse manual,
and was scary as hell, as we had to drill the V/B to do it, - the mimeograph didn't show the best detail, so getting a new V/B for a newstyle trans could be very expensive if you drilled incorrectly !
Once across the line, We just threw the shifter from 1st (Hi) straight up to the neutral gate and coasted.
Low gear just over-ran, - coasted , - which is perfect for street racing .