General purpose iPP grades are not very suitable for processing operations subjected to sever elongation flow field due to their tension thinning rheological behavior and low melt strength. However, by some modification in their structure, or even changing the shaping process design, they may readily be used in processes such as blow molding, fiber spinning, BOPP, etc. In this research we worked on five different available polypropylene grades which were characterized via rheology measurements to select and examine the molecular structure leading to a qualified grade for making highly stretched cast film. SAOS was used to determine complex viscosity, dynamic moduli, and the relaxation spectrum from which, using molecular viscoelastic theories, found molecular parameters including distribution of molecular weights. Elongation behavior was also evaluated in different conditions. Marked differences were observed in rheological properties and their microstructure prediction for one of the PP grades under investigation compared with the others. , PDI, λ, a shoulder appearance in the relaxation spectrum, etc., all were indicating a different structure for this particular grade. Existence of small portion of highly molecular weight chains was believed to be responsible for the observed different behavior. This modified structure brought about elastic response and melt strength, and replaced the tension-thinning behavior by a strain-hardening response in measurements of transient elongation viscosity. Finally the designated PP grade, from the effect of rheology, was examined in slit die extrusion followed by film stretching with a draw ratio of about 8 by combination of rollers to successfully make uniform highly stretched/oriented film.