Delta Downs, which added slot machines in February, is putting some of its increased revenue to good use with the newly created $500,000 Delta Jackpot, which will be contest on Dec. 21. The Delta Jackpot, a one-mile race for 2-year-olds, will be the richest Thoroughbred race ever offered at the Vinton, La., track.This year, only two other 2-year-old races are worth the same purse amount or more. The Oct. 5 Champagne Stakes (gr. I) at Belmont Park is worth $500,000 and the Oct. 26 Bessemer Trust Breeders' Cup Juvenile (gr. I) at Arlington Park is worth $1,000,000.The local prep for the Delta Jackpot will be the $75,000 Jean Lafitte Stakes, going seven furlongs on Nov. 24. Delta Downs opens its 80-day meet on Nov. 7 and runs through March 23 with a daily purse structure of about $160,000. There are 36 stakes races worth about $2.5 million scheduled for the meet.