Sept 6 is listed as open for drag racing but there is also a car show that weekend at the track, so it will probably be crowded.
This event is not listed on Calif speedway events calander, I found it on Calif car clubs event board.
Sept 6 and 7
Fontana, CA: The California Classic AutoFest; This promises to become the single largest Auto Extravaganza on the West Coast. The California Speedway in Fontana, California will be host to over 3,000 Classic Cars, 3,000 Import and Extreme Vehicles, over 1,500 Bikes, and 200 plus Big Rigs. Cruise the Track, RV Parking, Monster Garage, Celebrity Race and more... Location: 9300 Cherry Avenue; North of the 10 freeway. Info & map: www.thecaliforniaclassic.com. Telephone: 866-450-7469