"Boys and girls, get in your homemade, engineless, gravity-powered cars!" will be the starting command Sunday as Eden Park Boulevard in McKeesport is turned into a racetrack for the Greater Pittsburgh Soap Box Derby.

The competition begins at 9:30 a.m, and is called Step Back in Time. More than 30 entrants age 8 to 17 will try to win their respective divisions and represent McKeesport in the All-American Soap Box Derby in Akron, Ohio, on July 22.

The deadline has passed for any new entrants.

Cars will race, two at a time, in one of three divisions, stock, super stock and masters, based on the age and size of the child.

To help generate speed, the cars will take off from 45-degree starting ramps. Once on inclined, paved Eden Park Boulevard, they will race about 1,500 feet.

Each driver will race at least four times as it takes two heats to make a race, and the contest is double elimination.

Sunday's race features free parking and free admission, and refreshments will be sold. Spectators are encouraged to bring lawn chairs or blankets to sit on.

Under rules of the group, all car kits had to be purchased from the organization. The price is about $450.

All cars take roughly four to six hours to assemble, although a masters division car takes longer as it has a multipiece shell requiring fiberglass work.

Each child was responsible for building his or her own car, with some help from an adult.

"It's a great family affair where parent and child can bond together and teaches kids how to be more mechanical," said John Wagner, of West Mifflin, president of the Greater Pittsburgh Soap Box Derby.

His son, Tommy, 15, a six-year derby veteran, likes the speed in which he goes down the hill.

Mr. Wagner's daughter, Becky, who made it to the finals in Akron in 1999, helped Tommy put his car together. His other daughter, Theresa, painted and detailed it.

All cars are being inspected this week at the auto body shop at McKeesport Area High School.

Before the competition at 9 a.m. Sunday, there will be a celebrity race in cars provided by the derby. State Sen. Sean Logan, D-Monroeville, will defend his three-year title as top driver.

"I send them pasta every year," he said of opponents U.S. Rep. Mike Doyle and McKeesport Mayor Jim Brewster, "and that weighs them down."

A local radio station will hold a sports challenge contest at the track from 10 a.m. to noon.

For more, call: 412-462-1957; see: www.pghsoapboxderby.com; or e-mail: pghsoapboxderby@ yahoo.com.