Tony George, the head of the IRL and president of the Indianapolis Motor Speedway, will meet with ChampCar bosses Kevin Kalkoven and Gerry Forsythe next week, to thrash out a deal to combine the series' for 2009.
It is believed that the major sticking point that will be discussed revolves around the Motegi IndyCar race in Japan, with the race needing to move to September to allow the ChampCar showpiece race at Long Beach to keep its April date and form part of the re-united championship.
"It's as close as it's ever been to being together, but we don't know if we can get across the goal line," George told Speed TV. "But no one is giving up yet."
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Under the terms of the agreement that the trio are trying to reach, any ChampCar team that agrees to compete full-time in IndyCar, will be given a free Dallara chassis and Honda engines to aid them in their transition for the Panoz-Cosworth package they currently run.
The teams would also be eligible for the TEAMS programme, which pays $1.2 million to each car that competes full-time in the series as opposed to a prize money system.
It seems likely that any merger would see ChampCar wound up, but with the street races of Long Beach, Edmonton and Surfers Paradise absorbed into the IndyCar schedule.
Kalkoven told Speed TV: "Both sides want this to happen very much and we're working on it."
The IndyCar World Series, as it was then known, was forced to lose the "Indy" tag, after championship owners - made up largely of team owners - had a major fall-out with George over money at the end of 1995.
George set up his own championship, the Indy Racing League, with the Indy 500 central to its success, while the owners' series has Indy taken away from its calendar and was re-branded as CART, and then again later as ChampCar.
Despite constant growth for the IRL - which adopted the IndyCar tag in 2003 - both series' have suffered in popularity in recent years, thanks to the huge publicity machine that is NASCAR - leading to a desertion of drivers and fans.
Plans to merge the series before now have come to nothing.
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