This paper aims to model and simulate a design specification for a fuel cell electric powertrain tailored for Extreme H motorsport applications. A comprehensive numerical model of the powertrain was constructed using GT-SUITE v2024, integrating the 2025 Extreme H regulations, which include specifications for the fuel cell stack, electric motors, hydrogen storage, and battery systems. A detailed drive cycle representing the real-world driving patterns of Extreme E vehicles was developed, utilizing kinematic parameters derived from literature and real-world data. The performance of the Extreme H powertrain was benchmarked against the Toyota Mirai fuel cell vehicle to validate the simulation accuracy under the same racing conditions. The proposed design delivers a maximum power output of 400 kW, with 75 kW supplied by the fuel cell and 325 kW by the battery, ensuring optimal performance within the constraints set by the Extreme H 2025 regulations. Additionally, the design maintains an optimal fuel cell operating temperature of 81°C, as indicated in the literature. The logical methodology employed for developing the powertrain, which includes integrating regulations, designing the drive cycle, and optimizing the performance envelope, is elaborated in this paper.