The Indy Racing League says it is close to choosing between Dallara, Delta Wing, Lola and Swift for its 2012 chassis deal - and that it is open to using a radical design.
The IndyCar Series currently runs Dallara-Hondas dating from 2003, but wants to shake the championship up with a new rules package from 2012. It hopes to entice additional engine manufacturers to the series - most likely with turbocharged power - but had initially been expected to use a new style Dallara for the new era.
However IRL competition president Brian Barnhart says all four chassis builders are still in contention, with a series statement saying the choice is between "two parallel paths - one radical and one more evolutionary in design."
The IRL has stipulated that the new car must enchance safety, fit with a environmentally friendly future, allow close racing, offer more space for sponsors' logos, and be cost effective for teams.
It has also demanded that the cars are built in America. The present Dallara is made in Italy, but reports in America have suggested that the company would open a facility in the United States if it clinched the new chassis deal.
"For the last year we have engaged in ongoing conversations with four chassis makers on two different design tracks," said Barnhart. "Now we are receiving concepts and will make a decision soon.
"Our chassis is the most complex challenge in world motorsports because of the variety of race courses where we compete. It must be designed to run at 235 mph at the Indianapolis Motor Speedway and protect drivers and spectators in high-speed crashes. It must be able to perform on superspeedways, speedways and short ovals well as natural terrain road courses and temporary circuits.
"Our drivers take the greatest risks in the world of sports driving Indycars and it is paramount we have the best safety features designed into this next generation of cars.
"It is also important that we continue to develop more relevance between the new generation of Indycars and the cars that world manufacturers will be producing in the future.
"Finally, we have stipulated that the new chassis must be made in the United States, preferably Indiana, to take advantage of more competitive pricing and the existing American supplier network for parts and protect our team from issues with currency fluctuations."
Lola and Swift are both former Champ Car chassis suppliers, while the Delta Wing project is a radical new design created by former Lola designer Ben Bowlby, and backed by several leading IndyCar teams.