By JENNA FRYER, AP Auto Racing Writer

INDIANAPOLIS (AP) — A new rules package for Indianapolis Motor Speedway provided visibility issues for drivers. More troubling for NASCAR, though, is that after nearly five hours of practice Friday, there was little indication the changes will produce better racing.

NASCAR, in its effort to improve the on-track product, is using four track-specific aerodynamic packages to see what could be a better fit for the heavy stock cars. The package used two weeks ago at Kentucky was well-received by the drivers, but NASCAR switched to a high-drag setup for Indianapolis, where passing has always been difficult.

"Hey man, this is a big event for us, it's crucial that this event goes down as a good race every time we are here," Clint Bowyer said. "Settling for second-best is not an option. I'm proud that NASCAR realizes that and pushes hard to try to figure out something that is better than what we've had in the past when we come to such an important venue."

There were mixed opinions after three long practice sessions Friday, and many drivers said anytime they got too close to another car, the turbulence was so rough, they had to back off to avoid crashing.

"Passing will be tough to say the least, but we're trying something new," Denny Hamlin said. "I can't fault (NASCAR) for trying — they tried what we wanted to try (at Kentucky) and I thought we had a pretty successful race. Now we're trying something different. We'll see if it's better or not."

Last year's Brickyard 400, won for a record fifth time by Jeff Gordon, featured just 15 lead changes at the start/finish line — a number that NASCAR would like to see go up. The five-year average for green-flag passes for the lead is 16, and the margin of victory is a whopping 2.371 seconds.

With drivers feeling as if they had to back off whenever they closed in on another car, it's not clear if those statistics will be improved Sunday. Carl Edwards said "I couldn't get closer than 15 car lengths," to another car before he had to back off.

But Jamie McMurray, winner of the 2010 Brickyard, said it's too early to judge the package.

"We haven't had a restart, and to me, the restart is where this package is going to play a bigger role than in practice," McMurray said. "The thing with practice is that as you start to catch the car in front of you, typically their car is not very good. So, when you see somebody catching you fairly quick, you pull in so you can work on it and get your car better."

Part of the high-drag aero package includes a 9-inch spoiler with a 1-inch wicker bill. Although part of the spoiler is clear and gives drivers a gap, most seemed to think it wasn't big enough to see through from the rearview mirror.

"It's challenging to see," Joey Logano said. "I think I can see about five car lengths behind me, and any cars that are further back than that I can't see.

"That isn't the end of the world. If they're five car lengths back, you're probably not too worried about it anyway. When they get close is when you want to see it, but it is nice sometimes because we don't know. We'll see with this whole drafting package down the straightaway when that run is going to start."

Hamlin said he'd have preferred a clear wicker, but was surprised at how much he was able to see.

But that wasn't even Hamlin's biggest issue Friday.

His vision out the front windshield was severely hampered during practice when his hood flew open. The mishap apparently occurred because his team failed to tighten the hood pins before the second practice. When the hood flew up, it smashed his windshield and he had to return to the garage for repairs.

"The speeds that we're going, when that hood comes up, it just disintegrates and blows," Hamlin said. "The good thing is (it) didn't all stay together. The hood blew apart so much I had a gap there I could see.

"It blew the roof apart a lot. There is a lot of force there that tears up a lot of stuff anytime the hood comes up."