Mile Marker 505 505 Conversion Kit for Ford & GM 203 N

NP203 4x2 Conversion Kit with 449 Hubs Mile Marker NP203 4x2 Conversion Kit with 449 Premium Hubs delivers a complete heavy-duty solution for converting factory full-time New Process 203 transfer cases into efficient part-time four wheel drive systems. Designed for 1973 to 1980 Ford and GM 1 ton trucks equipped with the NP203 transfer case and Dana 60 front axles, this kit eliminates constant front axle engagement while preserving maximum drivetrain strength. Factory NP203 systems were engineered for full-time operation, keeping the front drivetrain engaged at all times, increasing component wear and reducing fuel efficiency. This conversion kit replaces internal differential components, allowing the transfer case to function in true part-time mode when paired with manual locking hubs. Included Mile Marker 449 Premium manual locking hubs are engineered for Dana 60 1-ton applications, delivering durable engagement and dependable axle control under heavy loads. By disengaging the front drivetrain during normal driving, this system reduces unnecessary wear, lowers parasitic drag, and can improve fuel economy while maintaining full off-road capability when engaged. Precision-machined components and decades of drivetrain engineering experience ensure reliable operation in demanding work and off-road environments. Designed for professional installers, restorers, and fleet operators, this complete conversion package modernizes classic full-size trucks while preserving their heavy-duty capability.