The continuous tightening of emissions limits is pushing the automotive world towards "green" alternatives to fossil fuels. In this context, hydrogen is a promising solution for the future of mobility, both with Fuel Cell vehicles and hydrogen internal combustion engines. The goal of the work is to design a hydrogen powertrain that meets the requirements of: High Performances, High Efficiency and zero emissions without after-treatment systems. In a first phase, after a detailed analysis of the different solutions, the hydrogen internal combustion engine has been selected as the most promising solution to meet both emissions and performance targets. Therefore a V8 turbocharged gasoline engine, currently used on a production car, has been converted into an hydrogen version capable to provide the same performances with negligible emissions.