An estimated 60-80% of air pollution caused by automobile exhaust gases has resulted in the establishment of a national goal to reduce automotive emissions significantly by 1975. Consequently, a government program to demonstrate at least two nonconventional automobile powerplants by 1975 has been set up by NAPCA, with a proposed two billion dollar budget for research.This paper summarizes the design and development of a small, lightweight, efficient, high-speed, turbine prime mover and a speed reducing gearbox. The turbine aerodynamic design and mechanical design are shown. The gearbox reduced the turbine's high (45,000 rpm) speed to the low (3800 rpm) output speed necessary for use in a conventional, three-speed automobile transmission. Complete fabrication of the turbine-gearbox was accomplished in approximately five weeks, and the problems and procedures used are described. The initial development tests are also summarized.