Chevrolet's complex IndyCar conversions

Kevin Bayless, the chassis and aerodynamics specialist at , has been assisting the teams to make the transition. "The IRL rules require that all engines use the same attachment points, so the Gen IV block bolts to the tub and the bellhousing just like the Gen III engine - but that's where the similarities end," Bayless explained. "Virtually every component on the car that interfaces with the engine must be changed in the Gen III to Gen IV conversion.

"All the engine support systems - the cooling, lubrication, exhaust and electronic engine management systems, the airbox, the clutch, the throttle cable, the bellhousing and the gearbox input shaft - have to be replaced or modified. Forty major chassis components have significant changes."

GM Racing and the Chevrolet teams have been operating on a tight timetable to have the cars ready for the Kentucky race. Several teams were able to get a head start by converting their spare cars. Others have had to make the conversion after last Sunday's race at Gateway International Raceway.

"The Panther Racing team did an outstanding job when they converted the first test car," Bayless said. "Based on their feedback, we modified the prototype parts and used them as patterns for the production run of parts. The experience we gained with each successive conversion meant that the process became progressively faster and easier.

"All our suppliers made a monumental effort to get parts to us as quickly as possible. I think Sam Hornish's performance at Michigan got everyone's enthusiasm up - not only the Chevy teams, but also the vendors."