A hybrid electric vehicle powertrain having a mechanical power source and an electro-mechanical power source, including a generator, a motor and a battery. Driving torque developed by the mechanical power source is delivered through one clutch of a geared transmission to a power output shaft. The electric motor of the electro-mechanical power source delivers driving torque through a second clutch of the geared transmission. A mechanical reverse drive torque is used to improve reverse drive performance. A reduction in duration of operation in a negative power split during a driving event is achieved to improve vehicle powertrain efficiency. A series drive is available as the mechanical power source drives the generator to charge the battery, which drives the motor. The generator may act as an engine starter motor.