In 1983, Theodore supplied factory-backed chassis for Tom Sneva and Kevin Cogan, fielded by Bignotti-Carter Racing. The chassis was practised by both drivers at the Indianapolis 500. Both would use a March 83C in the race, which Sneva won and Cogan finished in fifth place. Later in the season, Cogan used the chassis with a Cosworth DFX at the Promi Veal 200 at Road America and the Escort Radar Warning 200 at Mid-Ohio Sports Car Course. Cogan retired from Road America in 19th place due to an electrical problem and finished sixth at Mid Ohio and in 15th place in the final standings (most of the points were scored using a March chassis). The chassis was then used by Ed Wachs Motor Sports for Jim Crawford.