When discussing torque-converter stall speed, two terms, and, consequently, two entirely different numbers are used: "rated stall," commonly called "footbrake stall," and "flash speed." What's the difference? Footbrake stall is just that. You load the converter by stomping one foot on the brake and the other on the gas. Watch the tach. The rpm at which the converter overpowers the brakes is footbrake stall.

Flash speed is quite different. Flash occurs the instant you release the footbrake and the rotating inertia, which is stored in the engine-flexplate-converter, is released. In many cases, this flash speed can be anywhere from 500 to 2,500 rpm higher than the footbrake stall speed. Often, a racer will stage at idle, hold the brakes, and "flash" the converter by flooring the gas pedal the instant the last yellow on the Christmas Tree comes on