Indianapolis 500 Preview: What you need to know about The Greatest Spectacle in Racing

The 99th running of the Indianapolis 500-Mile Race goes down Sunday at the Indianapolis Motor Speedway, with pole-sitter Scott Dixon leading the 33-car field to the green flag at 12:15 p.m. ET.

Here's what you need to know:

Jeff Gordon will drive the pace car

(Courtesy: NASCAR)

NASCAR legend Jeff Gordon, who will retire as a full-time driver following the 2015 season, will lead the field to green Sunday afternoon after having been selected to drive the pace car.

He'll be driving a Chevrolet Z06 Corvette - the 13th time a Corvette has been chosen as the pace car.

"This is an amazing opportunity; I'm so honored," Gordon said, according to Kenny Bruce of NASCAR.com. "When I heard about this, my stepfather called me and told me kind of what was in the works between Chevrolet and Indianapolis, I was blown away. 'This can't be real, they must be joking.' To be standing here making that a reality is very, very exciting for me."

While he'll be around for the start of the race, Gordon may not last until the checkered flag. He'll watch as many laps as time permits, then fly back to Charlotte to compete in Sunday evening's NASCAR event, the Coca-Cola 600.

"This is my version of doing the double," Gordon said. "I think I got the best of both worlds."

Pole-sitter Scott Dixon is the betting favorite

Three-time Indianapolis 500 winner Helio Castroneves and one-time winner Juan Pablo Montoya opened as co-favorites to win Sunday at 5-to-1, but bettors getting in on the action on race day will notice pole-sitter Scott Dixon has climbed to the top of the board.

Here's a look at the first few names on the board as of Saturday evening:

(Odds courtesy: Bovada)

The race is blacked out for much of Indianapolis

Those watching from home will notice some improvements to the television coverage of the race, most notably the use of Ultra Hi Motion cameras, capable of producing images up to 20 times slower than live action to enhance views and replays.

But race fans in Indiana will have to make their way out to the track if they hope to catch the action. Since 1951, the race has been blacked out in the Indianapolis area. It's a move designed to encourage race attendance, preposterous as that may be.

The Indianapolis Motor Speedway seats over 250,000 people on race day. It's scheduled to undergo a massive renovation in advance of the 100th running of the Indianapolis 500 next year that will carry a price tag in the neighborhood of $140 million - with $100 million in bonds coming from the state to help fund the renovations.

Two nasty wrecks already in the books

In the first hour of practice last Wednesday, Castroneves entered the first bend, spun out, barreled toward the wall, then went airborne and landed upside down.

While Castroneves was able to escape without injury, James Hinchcliffe's wreck left him hospitalized and in need of surgery to his upper left thigh.

Hinchcliffe's car was travelling at over 220 mph when he lost control.

Hinchcliffe's injury was from a piece of the car's suspension breaking off and piercing his leg, not from the trauma of the impact.

The car ran into an area protected by a SAFER (Steel and Foam Energy Reduction) barrier which may have saved Hinchcliffe's life.

"He wouldn't be alive if not for the SAFER barrier," driver Tony Kanaan said, according to the Associated Press. "I really believe that."

The weather forecast has improved

Rain and thunderstorms bumped qualifying for the Indianapolis 500 from Saturday to Sunday, but weather is not expected to play a factor come race day. The race is expected to see dry conditions, with rain holding off until after the checkered flag.

Partial sunshine and temperatures in the low 70s are in the forecast for the start of the race, and temperatures will rise to around the 80-degree mark as the race progresses.