H. Clay Earles, 86, who as owner of Martinsville Speedway in the hills of Southern Virginia was a key figure in the early development of stock car racing, died Nov. 16 at his home behind the speedway.

Mr. Earles, who underwent back surgery a year ago, had been ill for the past week, said Steve Sheppard, senior director of corporate communications for the speedway.

A former operator of a service station and a pool hall, Mr. Earles started Martinsville Speedway in 1947 when he carved a half-mile dirt track out of the red clay near Martinsville, packed the track down with oil and other materials and advertised the race as "dust-free."

More than 6,000 fans -- some dressed for a big occasion -- came to that first race at the track, which had just 750 seats ready.

"It turned out to be the dustiest place I've ever seen," Mr. Earles recalled last year. "When the race started, it looked like someone had dropped the atomic bomb."

He then formed a partnership with former Washingtonian Bill France, the founder of NASCAR, the National Association for Stock Car Auto Racing.

The .526-mile track, which was paved in 1955, became an original venue in the first year of NASCAR racing.

The speedway grounds cover more than 300 acres, with seats for more than 70,000 people, six corporate suites, a 115-seat press box, high-rise grandstands and a fully staffed track medical center.

With France as his partner, Mr. Earles concentrated on the day-to-day operations. He developed a reputation in racing circles as an impassioned supporter of smaller, rural race tracks as larger venues were constructed across the country.

The son of tobacco farmers in southwestern Virginia, he worked as a furniture maker as a young man.

Soon he went into business for himself, first opening a billiards parlor that closed after only six months.

He then bought a service station and operated it for three years. That was long enough to turn a profit and afford a loan to buy the first drive-in restaurant in Martinsville.

Mr. Earles then operated his second service station, this time for 16 years, finally selling it in 1954 when the speedway required more of his attention and money.

He worked tirelessly at the speedway over the years and last took a vacation in 1959.

"Work is never finished at this track," said Mr. Earles, who regularly came into the speedway's offices in recent years. "Every day brings new challenges and ideas. And if we're not going forward, then we are going backward, and that's not going to happen."

His wife, Mildred Earles, died earlier.

Survivors include his daughters, Dorothy E. Campbell and Mary E. Weatherford; two grandchildren; and three great-grandchildren.