Zakspeed and Ford continued with the Mustang GTP program in 1984; the 2.1-litre engine was finally ready, and was used throughout the season. Ludwig was selected to drive the solitary entry at the Grand Prix of Miami, which was the second round of the IMSA GT Championship; a puncture damaged the front left suspension on his car, and forced him to retire after 31 laps, resulting in Ludwig being classified 25th. The team skipped the 12 Hours of Sebring, and next entered Ludwig and Rahal at the Grand Prix of Atlanta; this time, the fuel injection system packed up after 47 laps, restricting them to 48th overall, and 18th in the GTP category. The Los Angeles Times Grand Prix was little better; Rahal and Ludwig completed 74 laps before a valve in the engine broke, and forced them out of the race, resulting in a classification of 40th overall, and 20th in the GTP category. Two cars were entered at the Monterey Triple Crown; Ludwig drove one, while Bob Wollek drove the other. However, Ludwig retired on lap 45, and Wollek lasted an extra lap. The Grand Prix of Charlotte was even less successful; Ludwig crashed in practice and could not race, while Wollek retired after 21 laps, and finished 43rd overall, and 16th in class; however, he had also set the fastest lap of the race.