Norm Dianda doesn't expect to drive home truckloads of cash from the racetrack he's developing in partnership with Lucas Oil just east of Sparks.Instead, Dianda hopes that dirt-track racing provides an economic boost to Washoe County with the addition of yet another venue to the region's special events calendar. Dianda, the chairman of the board of Sparks-based Q&D Construction, and Lucas Oil are building a one-mile racetrack atop an old landfill on the north side of Interstate 80 at Mustang. The venue could draw up to 10,000 people to the region for an inaugural race August 25-26.Construction costs for the …