The 1998 AC Delco 400 was the 32nd stock car race of the 1998 NASCAR Winston Cup Series and the 34th iteration of the event.

[1][2] In the process, Jeff Gordon would manage to clinch his third career NASCAR Winston Cup Series championship, completing a dominant and historic run.

[5] Rusty Wallace, driving for Penske-Kranefuss Racing, would set the fastest time in the session, with a lap of 23.550 and an average speed of 155.465 mph (250.197 km/h).

[6] The final practice session, sometimes referred to as Happy Hour, was held on Saturday, October 31, after the preliminary 1998 AC Delco 200 NASCAR Busch Series race.

[5] Jeff Burton, driving for Roush Racing, would set the fastest time in the session, with a lap of 24.318 and an average speed of 150.555 mph (242.295 km/h).

[8] Mark Martin, driving for Roush Racing, would win the pole, setting a time of 23.394 and an average speed of 156.502 miles per hour (251.866 km/h).