The mutual desire for higher fuel economy and greater performance along with stringent emission regulations set by the government for diesel engines necessitates enhanced air-fuel mixing for proper combustion. The design of intake port plays a major role in an engine design, development and optimization, as it controls the power developed, fuel consumed and exhaust emissions from the engine. The effects of different geometrical parameters of helical port on swirl performance were studied. A methodology is proposed for the design of helical inlet port of diesel engine in order to achieve target value of 1.8 swirl number. The computational fluid dynamics approach is used for analysis of intake port performance. The port performance of prototype flow box was analyzed experimentally on a steady flow rig. The observed mean swirl number and flow capacity values satisfy the requirements.