The Datsun Truck line began in April of 1934 with the Model Thirteen. The datsun 521 was the improved version of the datsun 520. The datsun 521 was considered to have the style of a flat deck truck. This meant that it had a flattened bonnet, front fenders, and a new and improved grille design. The Nissan J engines were utilized in the datsun 521, later the NIssan L16, but always maintained a straight rear axle.