NASCAR's winds of change.(Knight Ridder Newspapers)

SMYRNA, Ga. _ American automakers didn't even know what the big Lockheed Martin Low Speed Wind Tunnel was for when it was built in 1967. They figured it was somehow related to making airplanes fly. When the Arabs put an embargo on oil in the early `70s, it didn't take them long to find out.

"At the time, cars were averaging 12-13 miles per gallon," said Gerald Pounds, who manages the enormous complex in this Atlanta suburb. "The government fuel economy requirements came out, and `` . . . they got interested real quick. All of a sudden, the `Big Three' was lined up at the door."

The line is still there, and it has grown. Recently, the Wood Brothers Winston Cup racing team had two haulers backed up to ground floor of the tunnel with three race cars inside for a few precious hours of "blowing."

At the end of their session, they headed back to their shop in Abingdon, Va., with a bank of knowledge that will help them keep up with the Hendrickses and Childresses of the racing world.

"We've spent quite a lot of time here this year, and our cars are better than they have ever been," said Eddie Wood, the team manager. "I attribute that to the tunnel."

Why wind tunnels?

The wind tunnel, which was designed to test aircraft, has over the years become a second home to race teams, particularly Winston Cup stock car teams. Of the 90,000 hours the tunnel has been in use, Pounds estimates that the time is equally divided between aircraft and automobiles, and that half of the time spent on cars is spent on race cars. That is a considerable amount of time for something that, 35 years ago, even Detroit didn't think was important.