trans brake vs launch control ?

My converter stalls around 3400 and i get the best 60" launching at 2200. It give you a run at the converter.
If i pump the pedal, so it will hold at the line and i launch with my foot to the floor it run a slower 60" and ET

Every car that I have raced ran a quicker ET the more I foot brake stall them. My D-50 will only foot brake stall around 2800, if I try to go higher it pushes through the beams. I still have had a best 1.33 60 ft. I wish I could stall it higher. I am thinking about sending my convertor back to get loosened up.