Mechanical design and development of the e-powertrain (traction, powerbox, battery pack and cablings) for the retrofit kit of a car converted from an internal combustion engine to electric. The work done is aimed at improving existing solutions of the BEVintage project. In particular, the activities involved: the mounting of the powerbox on the vehicle, the cad updating, the developing a new solution for the traction, the re-design of battery pack supports and the 3D model of the power and signal cables. In addition, a feasibility study was conducted on the Evergrin project regarding the battery pack to increase the capacity from 10kWh to 15kWh while maintaining the same available volume