Converter. Trans brake questions.

How a higher stall converter works goes a lot deeper than what rpm you leave the line at. Just pretend these numbers are accurate. You have a 4000 stall speed, your shift point is 6000rpm, and first gear at 6000rpm is 60mph. You leave the line at 4000rpm and start accelerating. At 40mph you will still be turning 4000ish rpm. The car accelerates brutally fast as it tries to catch up with the motor and converter. As the speed of the car catches up with the motor, the converter will let the motor run away from the car some more until you hit your shift point. The converter basically is like a bungee cord. The car is hanging from one end, and the motor is pulling on the other. It's difficult to explain in words. I'll see if I can find a video. I really don't think most people have ever driven a car with a top notch converter.