Best way to check it is have a playback tach, when you let go of the transbrake the conv will flash to a certain rpm, this is called the stall flash, then the ones that shift from 1-2 can see the rpm after the shift, this is called the stall recovery. BOTH of these are very important in the world of drag racing
IMO pulling a chip is a bad way to go about it but is better then nothing, it will be totally different on the track for stall flash.