Its actually in your ECM, you either have the M90 or M120. Both are have that functionality.
JJ, quite a few people are running the Mast M90 ecms on their gm takeout motors for tunability. This is one item thats tunable in their software.
Shirleys come to mind, they are running the M90 on LQ9's with cams and are getting low-mid 500's at the crank, and paddle shifting their 6l80's.
Back when I switched my old car, I couldnt find how you tune the pedal lag out of the stock ECM either. I didnt look super hard for a solution though as I had everything to switch to cable.