NASCAR Racing: Why 43 cars, nascar race, pit stall

Question
Why are there 43 cars in a NASCAR race?

Answer
It was mandated in 1998, a lot of factors went into the decision, including pit stall and garage space at tracks, the number of teams attempting to rull full-time at that time, purse figures, and the raceability of the number of cars on the track. They had it at 42, and reserved the 43rd starting spot for a past chamipion provisional, and the field was set at 43 in 1998.