Abstract: A system for automatically shifting the gears of a drag racing car transmission each time engine RPM reaches a predetermined level after leaving the starting line. The actual value of the predetermined level may be selectively adjusted by means of a potentiometer connected to the vehicle tachometer. A manually operable switch permits adjustment while racing an eight cylinder engine to only one-half the predetermined RPM level during adjustment. Additional potentiometers are preferably provided for limiting engine RPM to a first maximum value while racing the engine with the vehicle in first gear and held stationary at the starting line by the foot brake, and a second, higher, maximum value after leaving the starting line, both the first and second maximum RPM values being selectively and independently adjustable.