In 1983 Cogan began driving for Bignotti-Cotter Racing in the No. 6 Master Mechanic/Caesar's Palace March 83C-Cosworth DFX (numbered 16 at Indianapolis only). During the season results were hard to come by for Cogan with his best finish being a 5th place at the Indianapolis 500 where teammate Tom Sneva won. Helping neither Cogan nor Sneva was that Bignotti-Cotter began to develop the Theodore 83 rather than continue to use the proven March 83C. At the end of the season Cogan finished 15th in the CART standings and 6th in the USAC standings. At the end of the season Cogan and Bignotti-Cotter parted ways.