The engine will not rev past the stall of the converter. You can floor it with the trans brake on and the engine will only rev as far as the converter will stall. This is not a good way to launch the car. It is hard on the converter because it builds up heat. Also, if you leave flat against the converter you are not taking advantage of the torque multiplication of converter. I just learned this since joining here. I always have went dead against converter but now know different. I'm sure some of the experts will chime in here soon and give you the scoop better than I can.