Are you looking for a servo to upgrade a 1/5th model? Powerstar has announced the new PL-6213 HV High Voltage Servo designed for Big Scale Cars.
At operating range of 6.0v the servo pull up to 48kg/cm of torque at a speed of 0.15s and at 7.4v generate 62kg/cm to 0.13s. The PL-6213 HV measure 65.8 x 30 x 57.4mm.
Source: powerstar-racing.com