The invention relates to a modified zeolite catalyst, useful for the conversion of paraffins, olefins and aromatics in a mixed feedstock such as FCC gasoline that contain high content of olefin, aromatic and n-paraffin into isoparaffins. The invention further relates to the use of such a catalyst, for example but not limited to, in a process for the conversion of paraffins, olefins and aromatics in a mixed feedstock into the product having high amount of branched paraffins with decreased aromatics and olefins, a useful gasoline blend, with negligible production of lighter gases.