engine dies rough

HI guys ! Please help :) Two years ago i bought 1979 Chevrolet Camaro Z28 with some modifications (roll cage, SBC350 with Holley Street Avenger 80670 Dual Feed, Edelbrock Performer RPM (1500-6500) intake,MSD dist., Headers, B&M TH400 trans, new sparks, cables,). Car was in bad condition , so i...