MY BACK CARB IS MANUAL AND THE FRONT ONE IS ELECTRIC.I DISCONECTED THE ELICTRIC ONE AND THE MANUAL ONE I DONT USE UNTILL I CAN STOP FEATHERING THE GAS PEDDLE TO KEEP IT RUNNING. BOTH CARBD ARE 500 EDLEBROCKS. THE TIMING IS SET AT 8 DEGREES ADVANCE BUT IT WILL COUGH AND SPIT LIKE I THEW THE TIMING OUT OF WACK. THE DISTEBUTER IS NEW AND THE TIMING CHAIN ALSO. BUT.................. SCS