SPRINGFIELD, Ill. -- An autopsy on stock car racer Dean Roper showed that he died of a heart attack during a race Sunday, not injuries caused by the crash.

Roper, 62, had a history of heart trouble, which contributed to his heart attack, Sangamon County Coroner Susan Boone said Monday. The autopsy showed no injuries to Roper as a result of the wreck, Boone said.

Roper, of Fair Grove, Mo., crashed head-on into a retaining wall near the exit of the pits on the 17th lap of the Allen Crowe Memorial 200 at the Illinois State Fair in Springfield.

Roper, whose son died last October in a Texas crash, was the USAC Stock driving champion from 1981-83, and was the winningest ARCA series driver on dirt with nine career victories, including three at the Springfield mile.

His son, NASCAR trucks racer Tony Roper, was killed in the O'Reilly 400 at Texas Motor Speedway.