Hillary Clinton and Barack Obama are playing down expectations for the Indiana and North Carolina primaries, but the site for each of the candidates' rallies Tuesday could speak volumes about how they expect the night to end.

Clinton heads to Indianapolis, Ind., while Obama will be in Raleigh, N.C., at the end of the day. Both appear to be girding for a split decision.

The Democratic presidential candidates worked hard Tuesday to boost their margins without predicting anything definitive, concentrating on squeezing every ounce of support out of voters -- especially working class.

"I feel good," Obama said in Greenwood, Ind. "I think it's gonna be close. I don't think anybody really knows exactly what's gonna happen."

The two have strained over the past two weeks to shake the dynamic of the race -- which since late February has had Obama leading, but Clinton nipping at his heels.

And if Clinton wins Indiana, where polls show her leading by about 5 points, and Obama wins North Carolina, where polls show him leading by slightly more, the needle tilts only slightly.

Click here to read on-the-scene reports from Indiana by FOX News' Jeff Goldblatt.

"Every race is filled with the unexpected. You never know what's going to happen from day to day," Clinton said Tuesday in Indianapolis. "I never make predictions."

Clinton visited the Indianapolis Motor Speedway Tuesday with racer Sarah Fisher.

Clinton posed for pictures with the racer's pit crew in its garage and Fisher talked about parts of the powder blue car on display.

Asked by reporters what her message was by being at the Speedway, she said: "That we need to get on the track in America."

"If you want to go forward, you put it in D. If you want to go backward, you put it in R," Clinton said. Fisher helpfully pointed out that the race cars don't have reverse, to which Clinton replied, "That's right, it's full speed ahead."

Obama visited the Four Seasons Family Restaurant in the Greenwood, Ind., Tuesday, after hitting a factory for the midnight shift change just hours earlier at an Indianapolis auto parts factory.

"I need everybody's help," Obama told the workers. "This is going to be a close race."

Hoping to unwind during the day, Obama played two games of basketball in Indianapolis in the afternoon before leaving for North Carolina.

North Carolina and Indiana are the largest remaining races in the Democratic presidential nominating contest, with 115 pledged delegates up for grabs in North Carolina and another 72 in Indiana.

Expectations are low that either state will change the direction of the race that has so far been marked by an uncharacteristically long primary season, and is expected to last until June, or possibly not be settled until the August party convention. Both Clinton and Obama predicted they'd still be campaigning in June.

North Carolina and Indiana cannot mathematically settle the nomination. A candidate needs 2,025 delegates to win, and Obama had 1,745 to Clinton's 1,608 Monday.

Clinton saved her candidacy with her win in Pennsylvania, and campaigned aggressively in Indiana in hopes of denying Obama a victory next door to his home state of Illinois. The state is home to large numbers of blue collar workers who have been attracted to the former first lady, and she sought to use her call for a federal gas tax holiday to draw them and other economically pinched voters closer.

Inevitably, the issue quickly took on larger dimensions.

Obama said it symbolizes a candidacy consisting of "phony ideas, calculated to win elections instead of actually solving problems."

"It's a stunt," the Illinois senator said in Evansville. "It's what Washington does."

Obama's stance was backed up by 230 economists who released a letter Monday opposing the temporary tax break, which would take 18.4 cents off the price of a gallon if consumers got the full savings at the pump. Twenty-nine Democratic congressmen also released a statement Tuesday opposing the measure as "short-term and counterproductive."

Clinton shrugged off the blistering reviews, saying "Instead of attacking the problem, he's attacking my solutions," and ran an ad in the campaign's final hours that said she "gets it."

To a large extent, the gasoline tax eclipsed the controversy surrounding Obama's retiring pastor, Rev. Jeremiah Wright.

While polls always showed Indiana close, in recent weeks Clinton has closed Obama's double-digit lead in North Carolina.

Clinton campaign chairman Terry McAuliffe sidestepped questions when asked about fresh reports Tuesday from within the Clinton campaign that staffers were beginning to play down their possibilities North Carolina. The DrudgeReport cited anonymous sources in expectations of a loss of 15 points.

"I think we're going to be pleasantly surprised," McAuliffe told FOX News, adding, "I think North Carolina is very hard because of where we started this thing 25 points down (in the polls). I think we're going to do better than people had thought."

McAuliffe predicted a win in Indiana, though Clinton herself was more cautious.

Record Turnout

Record numbers of voters streamed to the polls in both states, which saw themselves -- like many states this cycle -- in the political spotlight for the first time in decades.

The sun had barely risen on polling stations when reports of lines, an excited electorate and a few minor glitches began to stream in.

It's going to be "a heavy voting" day, the Marion County, Ind., clerk told The Associated Press, as lines stretched toward ballot boxes. And a North Carolina elections official projected voters there would be "making history" in a state where nearly 500,000 voters cast early and absentee ballots by Monday -- more than half of all votes cast in the 2004 primary.

Indiana reported a handful of voting problems early in the day. Two inspectors showed up late. In two other precincts, ballots did not arrive, but they were printed to get that station opened by 7 a.m. And another voting district discovered problems with a touch-screen machine.

FOX News' Aaron Bruns and Bonney Kapp and The Associated Press contributed to this report.