Auto GP has attracted 21 registered cars for the 2013 season, which commences at Monza on March 23-24.
Following the demise of the Italian Formula 3 championship, Piercarlo Ghinzani has revealed his team's graduation to the category.
Team Ghinzani will step up with its Italian Formula 3 driver Robert Visoiu. Giacomo Ricci's much-anticipated race seat at MLR71 has also been confirmed.
Virtuosi UK has added Russian Max Snegirev to partner Andrea Roda. Campos Racing has switched its focus to a World Touring Car Championship partnership with Joan Orus this year, leaving newcomer Ibiza Racing, managed by Modesto Benegiamo, as the lone Spanish team.
Reigning champion Super Nova and Virtuosi UK are pursuing fielding three-car efforts.
2012 Curitiba double-winner Ombra Racing and Austrian team Zele Racing have yet to announce their drivers.
Delays in introducing a full quota of the new cars, developed by former Williams and Ferrari designer Enrique Scalabroni, are expected, meaning Monza is unlikely to boast a full field.
"We experienced some little delays in the delivery of the upgrade kits for the new cars," said series organiser Enzo Coloni. "It's a bit of an unavoidable risk when you put together such a new project in a short time.
"Unfortunately, as of today, we are not able to satisfy all the requests made by our teams in time for next week's opening event at Monza, but we're pushing for the next rounds.
"Having 21 cars in such tough economic times is not an easy task and I'm proud of the result we achieved."
2013 Auto GP line-up so far: Super Nova Vittorio Ghirelli Antonio Spavone TBA Virtuosi UK Andrea Roda Max Snegirev TBA Euronova Yoshitaka Kuroda Kimiya Sato Manor MP Ricciardo Agostini Meindart van Buuren Daniel de Jong* Ibiza Giuseppe Cipriani TBA MLR71 Michele la Rosa Giacomo Ricci Ghinzani Arco Robert Visoiu TBA Zele TBA TBA Ombra TBA TBA * Denotes part-season