What were the most drivers in a NASCAR race?
The most drivers who could race in a NASCAR race is 43 right now. But back in the 40's and 50's it was about 60.
To get a NASCAR license you can contact your local track, or you can call NASCAR in Daytona Florida and they will send you out the information. You don't need to hold a drivers license to drive on a race track. So, NASCAR drivers don't need one to race. You have to contact the sanctioning body and ask what the requirements for obtaining a NASCAR license entail.