A different kind of car than usual will be rolling around the half-mile oval Tuesday evening. Modified stock cars will be the cars making laps as the 20th Harris Clash takes place at the Knoxville Raceway. The Clash is put on by the International Motor Contest Association. Hot laps start at 6:30; racing starts at 7:15. Tickets are $15 for adults, $8 for kids ages 13-18; $4 for kids 6-12. Kids 5 and under are free.